The switch is a Miller No 42E. There is an original one one my Brothers B rap /34. I took it off one day and made two copies. One is on my Black B rapide cleverly plated JRO 101 which was in the hotel lobby at the 2003 Int rally. The other I gave to Dan Smith and is on his daughter's lowered B Rapide. Ernesto Morales in Texas was after some and was going to make a batch, but (I think) found some in Argentina, and didn't make any. Not any help but if ou have access to one and are even a poor amatuer lathe operator, as I am, It is not too difficult to reproduce. having said that I'm not doing any more!, unless you have a Comet gear box for swap! Also I see it mounted in the hole on the mudguard stay in the picture shown. If fact the early B's that they came on had no mudguard stay here and they were mounted on a little tab bracket, which also put them in a better position for the pull to operate.