Thanks guys for the tips. I pulled the switch assembly apart and the drivers window switch out and there were black soot deposits on the little copper contacts so I cleaned them, put it back together and it didn't work again. The window was fully up and I heard little "clunks" from the motor as if it was trying to work. So I gave up and went out for a few hours then came back and the window worked perfectly, so it's a mystery to me what the problem was, hopefully I'll have no more trouble but watch this space.