I too was aware of what a probable issue it was for something designed to work on Bantams with bits of cork stuck in them, but I figured they must work at least a little bit if they still sell the damned things. And THIS ONE was an updated version where the cork had been replaced with little rubber O-rings.
And guess what- the little rubber O-rings they used were the WRONG BLOODY SIZE!!!!!
I've replaced them now with some that work.
Honestly, I just don't see HOW something could have been so totally and stupidly wrong as this was. They sent the completely wrong part in the first place, and even THAT was fucked up inside! It absolutely beggars belief. No WONDER there's no British bike industry,