Senior 3rd Line IT Engineer

Senior 3rd Line IT Engineer
Location: London Bridge
Company: Managed Service Provider (MSP)
This role will be office-based for the first 3–6 months, with the option to move to a hybrid working arrangement thereafter.
Our client is a well-established MSP based in London Bridge. They are 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.
The Opportunity
We are seeking an experienced Senior 3rd Line Engineer to join our growing technical team. This pivotal role involves:
* Acting as the go-to escalation point for complex issues
* Managing core client infrastructure and cloud environments
* Ensuring centralized security and monitoring platforms run smoothly
You will work closely with our Service Desk and Project teams, maintaining high service standards, documenting solutions, and mentoring junior engineers through effective Standard Operating Procedures (SOPs).
Senior 3rd Line IT Engineer - Key Responsibilities
* Act as the primary escalation point for complex 2nd/3rd line incidents and service requests across infrastructure, networking, Azure, Microsoft 365, and cybersecurity.
* Manage and maintain client systems and centralized services, including Mimecast, Avanan, SentinelOne, MDR/XDR, Fortinet, DR/BC, Huntress, Autotask, and Datto RMM.
* Provide and present clients with centralized services reports and cybersecurity reviews.
* 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 with first-response troubleshooting.
* Contribute to continual service improvement by reviewing recurring incidents and identifying training or process opportunities.
* Mentor and provide technical guidance to Service Desk engineers.
* Ensure that all systems and processes align with best practices in cybersecurity, resilience, and performance.
Key Skills & Experience
* 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, and Autotask
* Strong troubleshooting, analytical, and communication skills
* Ability to work independently and collaboratively across teams
* Experience with Cyber Essentials, Cyber Essentials Plus, and other frameworks such as NIST, ISO27001
* Commitment to producing clear documentation and knowledge sharing
Desirable Certifications
* Microsoft Certified: Azure Administrator / Solutions Expert
* CompTIA Security+, CISSP, or similar cybersecurity qualification
* ITIL Foundation
* Vendor-specific certifications (Fortinet, SentinelOne, Datto, etc.)
Why Join the Company
* Join a technically strong, supportive, and collaborative team in central London
* Work across diverse clients, technologies, and industries
* Play a key role in strategic projects and continuous improvement initiatives
* Access ongoing training, certifications, and professional development opportunities
* Be part of a company that values reliability, security, and delivering excellent customer service