u/Mindless-Leg-7638

First time poster, never usually on Reddit but I surmised this might be the best place to identify this bike. Found very much abandoned in Bristol recently so took it in from the rain, can anyone identify this bike ? Says BSA, which from my knowledge of owning a motorcycle and having a friend owning a BSA motorbike means it’s surely somewhat vintage, if you need any more info or photos please let me know as I would love to restore this and use it as it fits me quite well , additionally if anyone can ID it I would love to know where to get aftermarket or original parts to restore it! Cheers