Managed to remove a well rusted on dynamo drive sprocket from a barn find A10. Tried a bit of heat and a slim legged puller. It was a real defiant one, no luck here, in the end took off the inner timing cover, stuck on, (so needed slide hammer and puller on the sprocket) then removed the idler gear from the spindle with nice 3 jaw puller, and took out the key leaving just the sprocket on the taper. Pushed it off the spindle in the big vice with a cylindrical spacer plus a bit of heat to help. Nice to save the part, rather than take the easy way with the angle grinder.
Swarfy.
Additional. No threads were damaged, no knuckles skinned, sprocket runs true, so all good for once.