Main dealer vs independent servicing

I have previously had my 2007 Jaguar S-Type V6 diesel serviced by the dealer because I thought that it was important for re-sale value. It's now done 85,000 miles and I'm considering independent garage servicing to save money. One of the main differences is the main agent uses very expensive oil (Castrol Edge 5/30, at £14 per litre) while the independent says 10/40 semi synthetic will be fine, since as the engine wears the thicker oil helps take up slack. Is this wise, or should I ask them to use 5/30 fully synthetic?
The Jag garage charges you £14 a litre. But it probably pays about £3 a litre. So you can keep the car on fully synthetic 5w/30 but at less than half the cost charged by the Jaguar dealer.
Answered by Honest John on

Ask Honest John