The Role The Senior Security Engineer is responsible for the day-to-day operation, maintenance, and optimisation of security platforms supporting a financial services client in a regulated environment. This is a hands-on engineering role where you will ensure security tooling is fully operational, integrated, and performing as expected. You will work closely with the 24/7 Security Analyst team, supporting investigations, resolving platform issues, and driving improvements across detection and response capabilities. This role is client-aligned with 3 days onsite in London. Key Responsibilities Maintain and configure security platforms including SIEM, XDR/EDR, vulnerability and cloud security tooling Perform lifecycle activities including patching, upgrades, and configuration changes Ensure security platforms are fully integrated across on-prem and cloud environments Monitor platform health, performance, and availability, resolving issues proactively Support service transitions, upgrades, and controlled change activities Act as escalation point for platform issues raised by the Security Analyst team Provide engineering support during complex incidents and investigations Implement platform-level changes to support incident response and remediation Support detection engineering including rule deployment, tuning, and validation Resolve data quality, alerting, and detection gaps impacting operational effectiveness Support automation and SOAR initiatives (e.g. Sentinel, Logic Apps)