paul and all......
I think it was a field or armory altering within the British Empire sphere. I think that this alteration was to fit a Brunswick with a different bayo bar, or to fit an old Baker rifle, or to fit the post Indian Mutiny issue of the basturd Brunswick rifles to Sikh units.
The Sikh guns were put trogether with parts of old Brunswicks, and lock plates from 1853 Enfields. This was done in India, probably, and who knows what was done to wood fore ends that were maybe oversized, or not so official bayo lugs. As you can see from my first image post, there exists another Brunswick bayo with the milled down handle.
I am working on the assumption that this was an inside job, (read that British Empire). This could be an attempt by constabulary forces to get matching bayonets on mismatched bayonet lugs. This was an attempt to "re-purpose" these bayonets to other Empire units or police.
BTW, The numbers and letter on your gun, will probably never be deciphered. The books on markings are incomplete, and it appears there may not have been a regulation as to how the markings were applied and meaning of such marks.
My whole theory is speculation. That is an old milling of your bayonet handle with a worn stamping over the milled area. That milling was not done by a re-enactor six years ago, so he could attach the bayonet to his Martini and run around his living room yelling "I am Private Hook" while watching "Zulu" on the tele!
Also, my research states that most volunteer bayonets have no maker marks so they were probably made by many makers in England and probably Belgium. The hilts, blades, buttons, and dimension were all slightly different from official marked bayonets.