OK, update on the mudflaps time.
Went on Friday afternoon to get them fitted and also listed a few other things like dash rattle, wind noise around door and rattle in rear seat. They came back to me 90 mins later, mudflaps no chance of fitting and have not had time to look at the other issues. VERY ignorant service lady who I quickly told to go away and get me the salesman who promised to world to me. On the rattle issues and door seal problem I could not believe they would not at least investigate to see if it needed any parts, she was happy for me to go home (25 miles) bring it back another day for investigation (50 mile round trip) then order parts if required and return another day for fixing (another 50 miles). Madness and rubbish customer service. Eventually someone agreed to test the car and diagnosed a faulty door seal within less than 1 mile which only took minutes. Very poor experience of a dealer who I have just started out in business with and my car is only 1 week old. Anyway, they are to come back to me on those issues.
I got them to give me a full set of flaps for me to try to fit but on a quick investigation it is not going to be easy. Even the backs do not fit well due to the different bumper shape and would need considerable trimming. Main dealer you said that rears should go on ok, has your dealership actually fitted them to a GTI yet and how did it go?
Also Main Dealer there is some suggestion that VW may bring out flaps designed for the GTI? Is your parts man able to get any info on whether this is true from VW and when is it likely. I would hate to spend hours modifying flaps to then find that proper ones are available very soon from VW.