Cloud Engineer - Microsoft 365 and Azure Tenant Separation

The Role - 6 Month Contract (day rate OR FTC)

Brook Green Supply (BGS) is an independent B2B energy supply company, creating risk management and energy supply solutions for the UK’s industrial and commercial sector.

The Cloud Engineer will lead the technical delivery of a Microsoft 365 and Azure tenant separation as part of a project-based contract engagement.

The role is based in London with hybrid working.

You will own the clean separation of identities, mailboxes, data, domains and security configuration between tenants, with minimal disruption to the business.

This specialist role suits an engineer who has delivered tenant-to-tenant migration or separation work before and understands the risks, dependencies and precise sequencing involved.

Success in this role requires technical depth, calm delivery under pressure, disciplined planning and clear stakeholder communication.

This is not a general Microsoft 365 administration role.

Essential Functions of the Job

• Own the technical design and delivery of the Microsoft 365 and Azure tenant separation from planning through to post-cutover stabilisation.
• Produce a detailed migration plan and runbook covering sequencing, dependencies, cutover windows, rollback procedures and communication checkpoints.
• Migrate identities, mailboxes, Share Point, One Drive and Teams data between tenants using appropriate tooling, ensuring data integrity throughout.
• Manage the domain namespace transition, coordinating DNS changes to minimise mail flow and authentication disruption.
• Rebuild and validate Conditional Access, MFA and endpoint security policies in the target tenant to maintain the security posture.
• Establish and manage coexistence services during the transition period, including mail routing, free/busy sharing and GAL synchronisation.
• Plan and execute device re-enrolment or migration where the endpoint estate is in scope, including re-enrolment into the target Intune tenant.
• Develop Power Shell and Microsoft Graph API automation for bulk operations, validation and reporting.
• Work closely with business stakeholders, security teams and third-party providers to coordinate cutover activity and manage risk.
• Provide clear documentation and knowledge transfer so the separated environment is supportable by the internal team.

Skills & Experience required

• Hands-on delivery of at least one end-to-end Microsoft 365 tenant-to-tenant migration or tenant separation, with evidence of user count, workloads moved, personal contribution and lessons learned.
• Practical experience with a recognised migration platform such as Quest On Demand, Bit Titan Migration Wiz or Share Gate.
• Strong Exchange Online migration expertise, including domain namespace moves, vanity domain release and re-addition, shared mailboxes, distribution lists and mail flow coexistence.
• Strong Entra ID identity migration experience, including cross-tenant synchronisation, B2B collaboration and the rebuild of Conditional Access, MFA and security policies.
• Confident DNS cutover skills, including MX, Autodiscover, SPF, DKIM and DMARC records across the transition.
• Strong Power Shell and Microsoft Graph API skills for bulk identity, licence and mailbox operations.
• Experience managing migration coexistence, including free/busy sharing, GAL synchronisation and mail routing between source and target tenants.
• Rigorous change control, cutover planning and rollback planning experience for business-critical migration activity.
• Able to communicate risk, dependencies and progress clearly to technical and non-technical stakeholders.
• Experience with Intune or endpoint migration at scale is desirable, especially device re-enrolment between tenants with minimal user disruption.
• Experience with Azure infrastructure migration, including subscriptions, resource groups, Iaa S workloads, Azure VNet or Express Route separation, is desirable.
• Network separation experience is desirable, including VLAN or subnet re-segmentation, firewall rule separation and VPN reconfiguration.
• Microsoft certifications such as MS-102, AZ-104 or SC-300 are desirable.
• Experience of separations linked to demerger, divestiture or acquisition unwind is desirable.
• Familiarity with Microsoft Defender, Purview and data loss prevention is desirable, particularly where data must be cleanly split between organisations.

Brook Green Supply is committed to ensuring equal opportunities, fairness of treatment, dignity and respect, and the elimination of all forms of discrimination in the workplace for all employees/contractors and job applicants.

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