Neil, I've got a 1932 Enfield marked No4 magazine that looks like it's a conversion from a SMLE magazine. Would the trials rifle magazines have been converted from SMLE ones or newly made "proper" No4 ones? It's been refinished etc before I picked it up with a mixed lot of stuff at an auction a while ago. Pics below - Let me know if it's of interest/use to you for your Trials (T) or if not and it's just a bog standard converted SMLE mag, I'll hang on to it as a spare for my No4. Kev