That’s downright bonidleness from the salesman. Nobody has to prove their status, that’s a reserve of the likes of Ferrari, Bentley, etc. I’d ring the dealership and either speak to or leave a message for the dealer principal and/or email the dealer and cc VWUK.
I have both on my shortlist but am a ways off yet. A lot can happen in 12 months. ?
Good luck.
? I will be remembered for nothing but had great fun doing it ?