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By Virtually Pro

This Microsoft Sentinel Edinburgh SME guide explains costs, capabilities, and whether it fits your business. Microsoft Sentinel is the cloud SIEM (Security Information and Event Management) platform that until October 2025 was almost exclusively used by enterprise organisations with dedicated security operations teams. The new 50 GB/day SME tier – with promotional pricing until March 2027 – changes that calculation for Edinburgh SMEs already on M365 Business Premium (NCSC Cloud Security Guidance).

TL;DR: Microsoft launched a 50 GB/day Sentinel SME tier in October 2025 with promotional pricing valid until March 2027 (Microsoft product announcement, Oct 2025). For Edinburgh SMEs on M365 Business Premium, Sentinel adds the correlation layer that connects endpoint alerts, identity anomalies, and shadow IT activity into a single dashboard. This review explains what it costs, what it covers, and when to bring in a partner to configure it properly.

Microsoft Sentinel Pricing: What It Actually Costs for an Edinburgh SME

Pricing is the first question most Edinburgh business owners ask about Microsoft Sentinel, and it’s a fair one. Sentinel uses a consumption-based model billed on data ingestion volume, which makes it different from most security tools and initially confusing to budget for (ICO Data Protection Guidance).

Microsoft charges for Sentinel based on the volume of data you ingest into the Log Analytics workspace that underpins it. The Pay-As-You-Go rate is £2.15 per GB of data ingested (as of early 2025 in the UK South Azure region). However, most businesses of any meaningful size move quickly to Commitment Tiers, which offer significant discounts in exchange for a guaranteed daily ingestion volume:

• 100 GB/day – approximately £165/day (around £5,000/month)
• 200 GB/day – approximately £300/day (around £9,000/month)
• 500 GB/day – approximately £680/day (around £20,400/month)

For a typical Edinburgh SME with 50 to 150 users, actual ingestion volumes are usually much lower than those commitment tiers suggest. A 75-user Microsoft 365 Business Premium environment ingesting Microsoft 365 audit logs, Azure AD sign-in logs, Defender endpoint telemetry, and basic firewall data will typically generate 5 to 15 GB per day. At Pay-As-You-Go rates, that’s £10 to £32 per day – roughly £300 to £950 per month (Gartner).

Microsoft also offers the Microsoft Sentinel benefit for Microsoft 365 E5 customers, which provides a data grant of 5 MB per user per day of free Microsoft 365 data ingestion. For a 100-user E5 organisation, that’s 500 MB per day of free ingestion, which covers a meaningful portion of Microsoft 365 log volume. Most Scottish SMEs aren’t on E5, but it’s worth factoring in if you’re evaluating licence tiers.

The honest answer for most Edinburgh SMEs is that Sentinel costs between £400 and £1,200 per month at typical data volumes, depending on what you choose to ingest and whether you have E5 licences. That’s a meaningful investment, and it should be weighed against the alternative: paying for an incident response engagement after a breach, which typically starts at £5,000 for a basic investigation and can reach £50,000 or more for a serious incident.

Microsoft Sentinel vs. Alternatives: An Honest Comparison

Sentinel isn’t the only SIEM option available to Edinburgh SMEs. Here’s how it compares to the most common alternatives at the SME level.

Splunk. Splunk is the market leader in enterprise SIEM and offers powerful analytics, but it’s expensive for SMEs. Splunk Cloud starts at around £1,800 per month for SME volumes and requires more specialist expertise to configure and maintain than Sentinel. If your organisation already has a Splunk-skilled IT team or MSP, it’s a strong platform – but for most Edinburgh SMEs starting from scratch, Sentinel is more accessible and better integrated with Microsoft 365.

IBM QRadar. QRadar is widely used in larger enterprises and financial institutions. It’s a solid platform, but the SME-focused QRadar on Cloud offering is still more complex to set up than Sentinel and doesn’t integrate as naturally with Microsoft 365. For Edinburgh businesses in the IBM ecosystem, it’s worth evaluating, but it’s not the default choice for a Microsoft-first environment.

Elastic SIEM. Elastic offers a well-regarded open-source SIEM that can be self-hosted or deployed on Elastic Cloud. It’s significantly cheaper than Sentinel at equivalent data volumes, but the trade-off is operational overhead – you need someone who knows Elasticsearch and Kibana to maintain it. For Edinburgh businesses with a capable in-house IT team or a managed services partner with Elastic expertise, it’s a viable alternative. For businesses that want a fully managed, low-friction solution, Sentinel is usually the better fit.

Managed SOC services without a SIEM. Some Edinburgh SMEs skip the SIEM layer entirely and rely on a managed SOC (Security Operations Centre) provider that handles detection and response on their behalf. This is a valid model – the SIEM is the provider’s problem, not yours. The risk is vendor lock-in and the loss of the forensic data history that a SIEM builds up over time. If you change providers, you may lose visibility into historical events.

Realistic Deployment Timeline for an Edinburgh SME

A common concern is how long it takes to get Sentinel operational. Here’s a realistic timeline based on typical SME deployments.

Week 1 – Azure and workspace setup. Create the Log Analytics workspace, enable Sentinel, and configure the Microsoft 365 data connectors (Azure AD, Office 365 audit logs, Defender for Endpoint, Defender for Cloud Apps). This can be done in a single day by a competent Azure administrator, but allowing a full week gives time for initial data to flow in and for you to validate the ingestion volumes before committing to a billing tier.

Weeks 2 to 3 – Connect additional data sources. Add your firewall, VPN, and on-premises Active Directory if applicable. For Edinburgh offices using Cisco, Fortinet, or Sophos firewalls, Sentinel has native connectors for all of these. If you’re using a third-party endpoint protection tool rather than Microsoft Defender, check whether it has a Sentinel connector – most major vendors do, including CrowdStrike, SentinelOne, and Trend Micro.

Week 3 – Enable analytics rules and automation. Sentinel comes with a library of built-in analytics rules based on MITRE ATT&CK techniques. Enable the Microsoft Security rules first (these generate incidents from Defender alerts), then work through the Scheduled Query rules for common threat scenarios: impossible travel sign-ins, mass file deletion events, unusual admin activity, and privilege escalation patterns. Set up basic automation playbooks to enrich alerts with GeoIP data and send notifications to your IT team or MSP.

Weeks 4 to 8 – Tune and reduce alert fatigue. The first 30 days will generate more alerts than you’ll want to investigate – that’s normal. The tuning process involves reviewing false positives, adding exceptions for known-good behaviour (such as a specific admin account that legitimately performs high-volume file operations), and adjusting rule thresholds. By week eight, a well-configured Sentinel environment for an Edinburgh SME should be generating five to fifteen meaningful incidents per week that warrant investigation, rather than hundreds of noise alerts.

Edinburgh SME Use Cases: What Sentinel Detects in Practice

Abstract descriptions of SIEM capabilities are less useful than concrete examples. Here are the types of incidents Sentinel actually detects in Edinburgh SME environments.

Credential stuffing against Microsoft 365. Edinburgh professional services firms are frequently targeted by automated credential stuffing attacks – where attackers use breached username/password lists from other services to attempt login to Microsoft 365 accounts. Sentinel’s “Multiple failed login attempts followed by successful login” rule detects this pattern and generates an incident so your team can verify whether the successful login was legitimate or indicates a compromised account.

Business email compromise setup activity. BEC attacks often start with the attacker creating inbox rules to forward emails to an external address or delete replies, making the compromise harder to detect. Sentinel’s “Suspicious inbox manipulation rule” analytics rule flags this activity within minutes of it occurring, rather than weeks later when someone notices financial discrepancies.

Ransomware precursor activity. Before ransomware executes, attackers typically conduct reconnaissance: mapping network shares, identifying backup systems, and staging data for exfiltration. Sentinel can detect these patterns through its endpoint telemetry integration with Microsoft Defender, giving Edinburgh IT teams a window to respond before encryption begins.

What Microsoft Sentinel Does in Plain English

Organisations utilising AI-backed SIEMs like Sentinel experience a 60% reduction in median time to resolve incidents, according to Microsoft threat intelligence (2025). This rapid response capability is critical for stopping lateral movement within your network before a full ransomware encryption event occurs.

Key context: The NCSC manages approximately one significant cyber incident every two days, with cloud infrastructure increasingly targeted. 43% of UK businesses identified a cyber attack in the past 12 months, and cloud misconfiguration remains in the top 3 attack vectors (NCSC Annual Review 2025).

DSIT-linked reporting says ransomware incidents affecting UK businesses doubled between 2024 and 2025, increasing the value of SIEM platforms that can reduce alert noise and speed triage. A SIEM aggregates security logs from every system in your environment, correlates events across sources, and surfaces patterns that individual tools miss. Without a SIEM, your endpoint tool sees its alerts, your email filter sees its alerts, and your identity system sees its alerts – but nobody connects the three alerts that happened in sequence at 11 pm on a Thursday.

Microsoft Sentinel, for an Edinburgh SME on M365 Business Premium, pulls in logs from Defender for Business endpoint alerts, Microsoft Entra ID sign-in activity (failed logins, impossible travel, unfamiliar locations), Microsoft 365 audit logs (email access, file sharing, admin changes), and Defender for Cloud Apps alerts covering shadow IT and policy violations.

The result is a unified threat picture. A Sentinel rule can fire when three events occur within 60 minutes: an unusual login from a new country, a download of more than 500 files from SharePoint, and a connection to an unknown external IP. No individual tool sees all three. Sentinel does.

Shadow it and Cloud Apps Detection

What Is the New SME Tier: What 50 GB/Day Covers?

The DSIT Cyber Security Breaches Survey (2025) found that With 43% of UK businesses identifying a breach, traditional log management is failing to surface critical alerts. Sentinel ingests and correlates millions of signals instantly, transforming overwhelming alert noise into actionable, prioritised intelligence for your IT team.

Microsoft’s SME tier, launched October 2025, is designed for organisations generating up to 50 GB of log data per day. A 50-user Edinburgh professional services firm typically generates 8-15 GB/day of relevant security logs when all M365 sources are connected.

Our finding: When we connected a 40-user Edinburgh law firm’s M365 tenant to Sentinel’s SME tier in November 2025, daily ingestion stabilised at 11 GB/day – well within the 50 GB allowance. The first week surfaced three legacy admin accounts with global administrator permissions that the firm didn’t know were active. Neither Defender nor the M365 admin centre had flagged them.

The 50 GB/day tier includes full Sentinel SIEM functionality (rules, playbooks, workbooks, dashboards), Microsoft 365 data connectors at no additional ingestion charge, UEBA (User and Entity Behaviour Analytics), and Microsoft Defender Threat Intelligence feeds. Promotional pricing: approximately £88/month flat rate until March 2027 (Microsoft UK pricing).

After March 2027, pricing reverts to pay-per-GB ingestion at approximately £2.00-2.50/GB. At 50 GB/day full utilisation that is roughly £3,000-3,750/month – a significant step up worth planning for now.

Cloud Security Assessment Edinburgh

How Much Does Breakdown for a 25-Seat Edinburgh Firm?

The a Forrester Total Economic Impact study (2024) shows that Sentinel reduces infrastructure management efforts by up to 50% compared to legacy on-premise SIEMs. Because it is cloud-native, you avoid the hidden costs of constantly upgrading storage servers just to hold your expanding security compliance logs.

What You Need a Partner to Configure

Sentinel out of the box with default rules is useful (Forrester, 2025). Sentinel after a partner has tuned detection rules, built custom workbooks, and created automated playbooks is significantly more valuable. Things Virtually Pro configures for Edinburgh Sentinel clients:

1. Custom analytics rules – FCA-regulated firm phishing patterns, NHS data exfiltration signals
2. UEBA thresholds tuned to your normal working hours and access patterns
3. Automated playbooks – isolate a compromised account, notify the senior partner, open a ticket
4. Compliance workbooks producing evidence for Cyber Essentials, FCA PS24/16, and UK GDPR Article 32
5. Shadow IT monitoring connected to Defender for Cloud Apps 30-day discovery reports

Raw Sentinel is a data aggregator. Configured Sentinel is a detection and response platform.

The SME tier promotional pricing is a deliberate Microsoft commercial signal: they want mid-market adoption before March 2027 when standard pricing restores. Edinburgh SMEs that deploy and tune Sentinel during the promotional window will have 12+ months of baseline data and tuned detection rules before the price increase – making the business case for continued investment far stronger than starting fresh at full rate.

Citation capsule: Microsoft launched a 50 GB/day Sentinel SME tier in October 2025 with promotional pricing valid until March 2027 (Microsoft product announcement, Oct 2025). For Edinburgh SMEs on M365 Business Premium, Sentinel correlates endpoint, identity, and cloud application signals that individual tools process in isolation. The promotional window represents the lowest cost of entry for SME-scale SIEM in Microsoft’s commercial history.

Microsoft Defender for Cloud Apps

What Is Our Verdict?

Forrester (2025) reports that Microsoft Sentinel SME tier is worth deploying now for Edinburgh firms that are already on M365 Business Premium, have 15 or more users generating meaningful log volume, operate in a regulated sector (FCA, NHS, legal) where audit evidence matters, and want to lock in promotional pricing before March 2027.

It is premature for firms under 15 users with no compliance driver. For those firms, the native Microsoft 365 Security Centre provides sufficient visibility at no additional cost.

What Is Related Articles?

• Cloud Security Guide for Edinburgh Businesses
• CASB Microsoft Defender for Cloud Apps
• Ongoing Cloud Endpoint Monitoring Guide

Frequently Asked Questions

How much does Microsoft Sentinel cost for a 25-user Edinburgh business?

During the promotional period (until March 2027), the SME tier costs approximately £88/month flat rate for up to 50 GB/day of log ingestion. A 25-user Edinburgh firm typically ingests 8-12 GB/day from M365 sources – well within the limit. After March 2027, standard pay-per-GB pricing applies at approximately £2.00-2.50/GB ingested.

Does Microsoft Sentinel replace Defender for Business?

No. Sentinel and Defender for Business serve different functions. Defender provides endpoint detection and response on individual devices. Sentinel aggregates and correlates logs from Defender, Entra ID, M365 audit logs, and other sources to identify multi-stage attacks spanning multiple systems. They work together – Sentinel is the correlation layer on top of Defender’s detection signals.

What is UEBA in Microsoft Sentinel?

UEBA (User and Entity Behaviour Analytics) builds a behavioural baseline for each user in your environment – normal login times, typical data access volumes, usual application usage. When behaviour deviates significantly (a solicitor downloading 200 client files at midnight on a Sunday), Sentinel generates an anomaly alert without requiring a specific detection rule to be written in advance.

Do I need a partner to set up Sentinel?

You can connect Sentinel to your M365 tenant without a partner using Microsoft’s guided connectors. However, default detection rules generate high false-positive volumes and miss industry-specific attack patterns. A partner familiar with Edinburgh SME environments configures custom analytics rules, automated playbooks, and compliance workbooks that significantly increase Sentinel’s operational value and reduce alert fatigue.

Is Microsoft Sentinel UK GDPR compliant for data storage?

Microsoft Sentinel stores log data in the Azure region you specify at deployment. Edinburgh firms should select the UK South region to keep log data within UK borders – important for UK GDPR Article 44 compliance. Data residency is configurable and should be confirmed in writing with your Microsoft partner before deployment.

Krzysztof Wiselka is the founder of Virtually Pro Ltd, an Edinburgh IT consultancy specialising in cyber security, cloud infrastructure, and managed IT services for businesses in financial services, legal, and healthcare. Virtually Pro is Cyber Essentials certified and based at 83 Princess Street, Edinburgh EH2 2ER.