MI5
MI5 North Operations Center, Roch Bank Place. Sometimes known as Park 66.
Also rumoured to have an office on King Street. Somebody has iris scanners on the doors of an office on King Street, so there’s something interesting there even if it isn’t MI5.
Also rumoured to have a presence in City Tower, M1 4BE - where UK Fast used to have a presence. This building is also of interest in general, being one of the tallest buildings in Manchester it’s perfect for installing microwave links on top of.