Found it!
Had to cut a hole in the carpet.
Relay #6 keeps locking up in a closed position, all the others working fine. If I wedge it open, then the switch works to open the window, but if I manually close relay #6, then it also blows a fuse. I have checked the earth wire to the motor for continuity and it is fine, so I guess this module must be faulty, doesn't look cheap to me and I suppose it's not repairable, (If I knew where/what the fault was in the first place!)
I don't suppose there is any way to test it before replacing it?