What might an Admiralty employee at Corsham have been doing?
Short answer
Probably work connected with HMS Royal Arthur's petty-officer training school.
Notes
Corsham housed the petty-officer training establishment associated with HMS Royal Arthur. An Admiralty employee there was probably involved in that work. The family member's actual job is not identified, so the connection remains probable. Philip's own instructor appointment places his postwar service inside the same institution. The Navy needed capable junior officers for a demanding audience of experienced ratings.