Thank you for remembering, Mr Charvey & Vincent, and coming back with info.
Those bits, Vincent are very interesting but I'm wary at the moment of importing things from the EU; there're lots of stories of delays, taxes, duties, etc that worry me, otherwise I'd be very keen. Have you any advice on purchasing these items?
Regarding your followers, Mr Charvey, I'm after not after the cam followers but the vertical tubular items about 4 inches long and about 3/4 inches diameter that the followers lift and which transmit the action to the base of the valves. If you have one of these that I might measure I'd be very grateful.
Once again thank you both for your advice and consideration, MikeN.