Saw some lovelly examples of these in LA, they're raced in the states and I'll be going for the pint sized racer look - this is a nice one:
It got delivered today, so while I'm waiting for parts for the triumph I made a start. Had the engine out in no time and got the top end stripped. Pistons are rusted in the bores, but the bottom end looks clean and appears to turn freely, cam and valve gear looks ok although there is some rust in the combustion chambers which should clean up ok. Fingers crossed I can get the pistons out easily and it will just need pistons, rings and a rebore.