Hi Jim
I am almost embarassed
to respond to your friends query about the Bessa. I know I owe you a gazillion email responses. I am making headway with the last item you were asking about.
Anyway I have a bocklet called "Tank Guns ands Mountings". It is book 1B and deals with the 6PR and the Besa. It shows some exploded views of the Besa, stripping, assembly, stoppages and tools. There is also a page on headstamp markings and a photo of the ammo box. Tomorrow I will try and take a couple of photos and post them if they will show any detail.
Cheers,
Barry