HQAC have always made it quite clear to squadrons that they do not keep historical records of them, so please don't ask.
I would suggest the local paper at Bourton might be a good place to start.
Now if it had been 1365 (Aylesbury) and not 1356, I could have helped!
My 'original' squadron was 2204 (Chesham) Sqdn which was originally 2204 (Germains School) Sqdn and we had a trophy dated 1948 which indicated that the local squadron was originally 1414 (Chesham and Amersham) Sqdn, so there could have been a post war re-numbering of squadrons.