Senior 3rd Line Support Engineer

We are a well-established Managed Service Provider (MSP) based in London Bridge. We’re a close-knit team of 30 IT professionals delivering end-to-end technology services and support to a diverse range of clients, with a strong focus on reliability, security and customer care.

We’re looking for an experienced Senior 3rd Line Engineer to join our growing technical team. This is a pivotal role within the business — acting as the go-to escalation point for complex issues, managing core client infrastructure and cloud environments, and ensuring our centralised security and monitoring platforms run smoothly.

You’ll be working closely with our Service Desk and Project teams, ensuring high service standards, documenting solutions and helping mentor and guide junior engineers through effective Standard Operating Procedures (SOPs).

• Act as the primary escalation point for complex 2nd/3rd line incidents and service requests across infrastructure, networking, Azure, Microsoft 365 and cyber security.
• Manage and maintain client systems and centralised services, including: Mimecast, Avanan, SentinelOne, MDR/XDR, Fortinet, DR/BC, Huntress, Autotask and Datto RMM.
• Collaborate with the Project team on deployments, migrations, automations and upgrades across on-premises and cloud environments.
• Develop and document Standard Operating Procedures (SOPs) to assist the Service Desk in first-response troubleshooting.
• Contribute to continual service improvement by reviewing recurring incidents and identifying training or process opportunities.
• Provide mentoring and technical guidance to Service Desk engineers.
• Ensure that all systems and processes align with best practices in cybersecurity, resilience, and performance.

• Proven experience in a 3rd Line / Senior Engineer role within an MSP environment.
• Strong knowledge of Microsoft technologies including Azure, 365, SharePoint, and Intune.
• Excellent understanding of networking, firewalls, VPNs, and Windows Server environments.
• Experience with RMM tools, security platforms, and endpoint management.
• Familiarity with tools and platforms such as: Mimecast, Avanan, SentinelOne, MDR/XDR, Fortinet, Huntress, Datto, Autotask.
• Strong troubleshooting, analytical and communication skills.
• Ability to work independently and collaboratively across teams.
• Commitment to producing clear documentation and knowledge sharing.

• Microsoft Certified: Azure Administrator / Solutions Expert
• CompTIA Security+ or similar cybersecurity qualification
• ITIL Foundation
• Vendor-specific certifications (Fortinet, SentinelOne, Datto, etc.)

• Be part of a friendly, collaborative, and technically strong team in the heart of London
• Opportunity to work across a wide range of technologies and industries
• Involvement in strategic projects and continuous service improvements for a growing organisation
• Ongoing training, certification, and professional development support