I've had a few BSA bicycles in the past, I think most big towns had a bicycle maker over here at one time .
Lots of gunmakers did other jobs too.
I was in a local gunmakers premises a couple of years back and a guy came in to pick up a set of door lock springs he'd made for his 1920s Rolls Royce.
He is a Stocker by trade and I believe he also made some lovely domestic furniture.
I suppose it all goes towards paying the bills.

Rust never sleeps !