I think Waitrose really do try their best with customer service.
Several years ago we bought one of those Bronze Turkeys for Christmas and in spite of cooking it exactly how you are supposed to , you know - cover it with muslin, baste every hour blah, blah, blah!!! It was as dry as you can possibly think and was so sad because my husband really loves turkey!
I cut off a large slice and took it back on the first day I could after Christmas. The Manager took one look at it, and then went away, returned with £100 of Waitrose Vouchers (even though the turkey cost about £50) and did not even ask to see the receipt.
So here's hoping for another DRY turkey!! No joking apart, they never ever question returns and always go the extra mile when you ask about anything.