As I understand it earlier Bell tgt days would have been Milita's and Gems, not much more around in fairness. Loads of UK businesses imprted Milita's many with their own names added at some point. L J certainly imported them and as I understand it cut them up; added his gas tap mod [devised with his gas fitter neighbour's help] and cocking mech thus developing the rifle that pretty much revolutionised Bell Tgt. As far as I'm aware Frank's book is still available but I think in digital form. I'm lucky I knew Frank very well and have a dedicated signed copy. For sure the links to Bell sites as shown will provide a mountain of info.
It does appear that it was a sport set in local areas; Bridgend and Bridgnorth being amongst the oldest, and surprisingly there were a lot more ladies involved in the early days, again I think Bridgend can show it.
I shoot on the Wolvwerhampton A R L formed as a Bell Lge in 1972, aged 75 I've shot in every year from 1973, now proud to be Chairman.
To anyone wanting an amazing sport, try it !
To existing shooters keep it up you're part of of a legendary sport and long may we all continue.