Just thought I'd update this now the car is somewhere near right. The actual claims handling firm (connexus, operating as SEAT ensurance) have been fine, courtesy car was a mondeo estate (for a leon) which was the nearest they could get with cruise/bluetooth the week before christmas.
The garage have been woeful though. First time I went to pick it up I didn't even leave the office as you could see problems from the other end of the carpark (lights not refitted properly, number plate not replaced etc). Second time the paint didn't match, orange peel & runs everywhere, broken clips on the trim, big patches of primer showing inside the bootlid etc. Third time looked fine, but turned out to be leaking washer fluid all over the boot. Fourth time leak fixed, but broken clips on the trim again, so grab handles are unusable and it rattles all the time. The paint is still not perfect, theres orange peel on the inside of the boot lid, but
tbh its not awful, and you wouldn't notice it if you weren't looking for it.
Needless to say, not a happy bunny. I can't see how it can be symptomatic of all the work they do or they'd be out of business, unless most people just don't check the things?