Thank you for answers and experiences folks. I'm currently away so haven't had chance to take it in to be looked at yet.
I'm not mechanically minded so was wondering how the faulty DMF would be identified? If Audi don't play ball I'm assuming I have the right to request the broken part and then have it examined independently? I'm prepared to battle with them because this isn't a cheap job which is likely to occur again. I also spoke with my dad who have a 2014 a4 with 25k who said he has the judder and a colleague has a q5 with the same at 40k.
I feel a trip to Mercedes will be on the cards