Late on this, the common long socket bayonet will have several markings. The proof inspection stamps, which will be Enfield or BSA & M Co. Then "R" which is the post 1881 bend & retest test marks. Look out for rack numbers and often "F.W.A." Fort William Arsenal and on those emanating from Nepal the Nagri regimental texts on the plain faces.
A small crown and "B.R". is Birmingham Repair, Bagot Street.