Timkel thanks for the reply. Many many years ago some museums (and dependant upon the personalities involved) had the mission of building upon and improving their collections. I am sure there are still some museums who choose to maintain what they have and not evolve and that is fine, but for me under certain conditions museums should develop. I was lucky then in those days to have some very desirable vickers, Lewis and hotchkiss accessories and therefore in controlled conditions I obtained these 3 as trades. The museum still has examples like this and 08 so therefore it was a win win for them, which realistically is the only way any decent museum would operate!
Nowadays it is so much harder to do this due to Govt legislation following abuses so as ever a minority spoil it for the majority. I know for a fact many private collectors could add significant value to recognised collections/museums and concurrently enhance their own collections but really whichever country you are in it is next to impossible. So a long reply, and now to find some period imagery of these items in action!