I am looking into the service of a flight engineer who initially joined the RAF as a ground engineer before remustering in early 1942. I am a little baffled as his service number is 652403 which was apparently in a block issued to civilians from 1938.

He joined in August 1939 so the date frame is okay, but certainly was not a civilian. His first posting apparently No. 3 depot, and his next No. 3 Wing later the same month. Which training school was this?

Can anyone unravel the mystery?