Gilly, a frequent failure part in 123 and 126 window mechanisms is the little square plastic slide that the window sits in. I've replaced at least 3 of these on 123's and 126's, myself - very easy fix. Are you saying the mechanism in this car is different - doesn't have this vulnerable little slide, or you don't know/don't remember? Of course, the lift arm can break or warp, etc., and the motor can quit, switch not switch, etc.

Wilton