I'm so jealous Robin, I don't trust any of the dealers in my area one bit
I'm the same. I've been complaining of my boot literally filling with water for the last three winters - at least 2" deep in the spare wheel well. It has had one 'master technician', then another, then their body shop, then their 'Eos roof expert' - even though three winters ago, I personally told the dealer principal (and everyone downwards) exactly where the water was leaking from. I couple of weeks ago, I literally blew my top, walked into their workshop, jacked up the front, and with the help of their tiny service reception girl, had to physically show them where the leak was coming from.
Every time it goes in, they always miss something off the job, or leave the interior like the inside of a pikey travellers transit van. And it isn't just my local stealer. Two other nearby stealers are as bad too. And as for Ipswich VW, don't get me started on them!
My local Audi stealer is better, but they still can't properly diagnose faults correctly . . . . I really do wonder why Volkswagen Group UK allows such incompetence in all their dealers. That isn't to say they are all bad, because as Robin can testify, there ARE some good dealers - but sadly, the 'minimum standard of competence' accepted by VW UK is grossly below what should ever be deemed acceptable.

I've actually had much better VAG service in France and Andorra, even with my pidgeon french and catalan!