Just spoken to one of the service engineers at Morgan and he said they had noticed the problem and later cars had been fitted with a 30A fuse.
So no problem to leave the 30A in and he didn't think there was any need to remove or service the starter motor.
I would say how lucky we are as owners on the odd occasions I have needed advice the factory have always been incredibly helpful, I doubt that could be said of other manufactures.
Worthers +8