Thanks for those contacts, I've used them previously with success. The parts I'm looking for are 4sp gearboxes, crankcases etc, all the basic bits which, if purchased in separate parts would cost a fortune to buy from the UK. I use those suppliers for the consumables, eg pistons, rings, gaskets etc.
I've just returned from a short rip up the road on the beast, with a fairly good 7E motor fitted. Went well, bit noisy for Ferny Hills though. Don't do it too often, don't want to upset the neighbours.