I suggest you follow my example and appear in person at the dealer a few weeks before annual service to flag up a warranty claim on the insulation at the same time as booking the service. You want them to look at it with you so phoning is probably not the best approach. You want them to confirm there and then, or within a few days, that it is a warranty replacement, so they have time to order the part before your service date and get both done in the one visit.
In fairness to Cameron VW in Perth, where I have always had my cars serviced, they were very supportive and got back to me within 24 hrs to commit to a warranty replacement both times.