Are these gliders airworthy? If not, it's a pity - someone had our club T21 at over 7000 feet last Sunday and it's a waste to keep them locked indoors.
There's a guy named Richard Cawsey who has a website
www.rcawsey.fsnet.co.uk which includes the Slingsby gliders production lists.
He was able to give me a lot of information on the service record of our T21, so he can probably help with the SW ones. Try emailing him direct.
He's got WB941 listed as at the SW museum but nothing on XE 785 so he'd probably like to know (+ any pictures)
As far as I know, the St Athan stencil means that the glider went through the reconditioning workshop at St Athan at some stage. "Titanine" was a type of fabric dope. The number may be a colour code (does anyone know?). Our T21 has the same stencils (with different numbers) on all the different coloured sections.