I've always found @vwukhelp on twitter to be very responsive
Interesting update... I reached out on Twitter as per the advise above, and got a message back very quickly. Couple of phone calls later and VW Customer Service are all over it. Fantastic service.
No result as of yet, but CS are contacting the dealer to establish whether or not they did actually apply for the warranty claim, or just took a judgement call on whether or not they thought it would be accepted.
They agreed that the trim should last a lot longer than 2 years without flaking off. I emailed them the link to this thread so they could see the pictures and the evidence that other members had trim replaced under warranty.
Been promised a call back before COB tomorrow so here's hoping.