Hi Trev...
Certainly an export model as it still has the South African number plate attached, markings on the back of plate suggests Pretoria, I don't think the bike has rolled on a British road yet as it had been tucked away at the back of the previous owners garage for the last ten years since it arrived back here.
I looked closely at the short rear mudguard and it looks rather crudely cut although I'm sure it is the original one fitted at the BSA factory, after all what rusts out there in the African climate? I also noticed while working on the bike today that the alloy finish is better than that of my home market A10s. Seems we thought more of you overseas guys than ourselves.

Gearbox STD unfortunately.
Sent off the application for a machine dating certificate today so that'll tell us a bit more about it.