Having stripped all useless unnecessary detritus from the bike, I've found multiple nests of small creatures, a whole load of rusted on bolts, and a couple of spots on the frame that need welding, on the rear engine mount brackets..
Got a mate coming round next week with a couple of old small tanks we can try for size. That'll define the lines of the bike I reckon.
Does anyone know if the airbox can be taken off without taking the carb off? I've undone everything I can see, (3x cover screws, 3x box mounting bolts, 1x clip round the carb intake) but it ain't shifting yet..... There's not a lot of wiggle room in there.