They were indeed. They actually kept badgering him after he'd sent the information. He had the receipted invoices from VW for the correct oil, and was able to supply these. After all, he knew he was servicing a car under warranty, this was something I discussed with him before actually buying the car, never mind letting him service it. He knew he had to do it by the book.
Also, this is a fairly small village. Andrew relies on people in the village patronising his garage. If it got round that he'd cost someone a £5,000 repair bill by invalidating their warranty (and let me tell you, things like that get around pretty fast), he'd be looking at a serious dent in his business.