Thanks for all the info. I locked the output shaft by sliding a big screw driver through the universal joint there and tapped the fan pulley with a drift and turned it slightly then jiggled it forward a bit using a couple of large screw drivers until I was able to get the tangs of the three jaw puller behind it and then just pulled it off. It is probably meant to be a slide on fit but as you say, rust and a bit of aluminium growth made it overly tight. I'll clean it all up before it goes back together.
I checked the cowl from the inside, no layers of paint there, and there is no sign of any punching anywhere for ID numbers. I hosed all the crud from around the engine, the machine went through the floods, and then whacked a pipe wrench on the front and it is turning over pretty easily with plenty of wheezing coming from the ports so there is a chance I can get the old girl running without too much problem.
Not bad for $20 from the tip shop hey?
