The driver's side window failed to lift a while ago so. after an epic struggle to get the motor and regulator arms out the reason for the item's failure was clearly the cable snapping, at the bottom end. Taking the cover off the winder, was also a revelation as the snapped cable had jammed the worm gear. (hence the problem dropping the window to remove the mechanism). The motor checked out as still fit for service.
All the parts are serviceable so I figure that a cable repair kit sh