Owners club looks to be post war stuff, very little info about about theseSorry, can't really help you,....I'm guessing that there must be an owners club/forum dedicated to this bike though?
I'm sure that you'd find diagrams/pictures if you went down that route.
This is we think Enfields own its defiantly not an Albion and its hand changeVilliers used a 3 speed Albion for many years, and Royal Oilfield used a 4 speed on the 350 Bullet until they went LH change.