Strictly speaking, its probably on a long life service schedule, aint no way mine was going 19/20k on the same oil from new !!
I did my own oil change at 5k, then VW service at 10k.
If the previous owner bought the 3 services for £250 from VW, then it may well have been done at 10k. Prices for sevices vary with dealerships, give your local a call, I wouldnt accept the current owner/garage doing the service for you, you need the VW stamp in the book...but I`m sure you know that
