Norwich Paul may be able to throw some light on this query.
This building is identified in British Airfield Buildings (Vol 2) Page 34 as a Magazine to AM Drawing 4279/37.
http://www.flashearth.com/?lat=53.36391 ... =0&src=msa
1. This location is unusually close to a hangar for an explosive store. Less than 150 yards! What was it's intended function?
2. Manby opened in 1938 and was a 'expansion' station and would have had a bomb store to AM Drawing 3054/36. What was the location?