Unfortunately you won't get a choice where the work is done as it going to be paid for by VWUK who will dictate who does the work. Iv worked in dealerships for years and have a good knowledge of how the warranty process works. Warranty jobs are a ball ache for the dealer as the process the manufacturer expects the dealership to go through is the biggest box tick excersise you'll ever see. For example the battery dies within its warranty period. The dealer and owner know that the battery is shot to sh*te and needs replacing. To get payout for a new battery it needs to be proven to be faulty so a diagnostic machine is connected. It does its testing then charges the battery. It's tested again and when the results come back the manufacturer will pay for a new battery. This is a 2 day process that requires the car to be at the dealers workshop......the manufacturer will pay 1 hour labour for this!
With paintwork claims in general the allowed times are bearly enough to prep the panels properly so the end results can be shocking! Your best bet is to let the company who is doing the repair know that the car is something you take great pride in and you are reassured to know that a Manufacture approved body shop will be doing the repairs so you know the end results will be as good as new and meet or exceed manufacturers standards. I'd suggest emailing something along those lines and keep the email. This should let them know your expecting what's suggested in the VW blurb and are going to be fussy about your pride and joy without sounding like a dick. If it goes wrong you'll have all communications via email to use. Taking pics is a good idea too as previously mentioned, but only use them if you need to.
Hope it all goes ok for you