Trading Standards will advise initially to let the bodyshop to have another crack at doing a better job on the paintwork. However, if you are not happy then you could push for it to be done at a bodyshop at your choice but that would be unlikely unless they bodge it again
From your description they have rushed the paint job and not allowed sufficient time between coats to let the paint etc cure
T-shirt and a car is not a great comparison; t-shirts are throwaway items........ 
I don't think i'll need to go to trading standards tbh but who knows, i disagree that a shirt isn't a fair comparison, why should i let anyone have a stab at fixing an inferior product? In hindsight i never should have signed for it, i don't think it's acceptable for it to be anything less than perfect.
So sorry to read this Jimble.
You waited so patiently for a long time without kicking up a fuss and now this.
If you can't get on with the auto box then that's just the way it is and at least you've tried it, the manual is really nice btw.
What next? Would VW consider swapping for a manual? Or do you want the R?
Maybe you should mention your are a mod on here, may help push things along in your favour, maybe not.
Difficult one. 
Got to wait and see what the dealer says on monday, i've told them i'm a mod on "an internet forum" and the car currently has the stickers in the windows soo??

I would probably lean towards another GTI or an R which would probably be easier tbh, i just don't know what i'll drive until it's built? I test drove an Evoque today as i was near a dealership, nice car but my god it's gutless!! 2.2 SD4 with 190 bhp but my works outlander has more go and thats a fully laden works van!!