Current XF's require you use Castrol Oil. This oil is only available from a Jaguar dealer. To change engine oil and filter costs £169.00. For the last 15 to 20 years have always used Mobil one. That includes 2 Jaguar 4.2 XK's S Type 2.7 Diesel, 2.7 Diesel XF. Current car XF 2.2 I purcase Mobil One locally for £25.00 for five litres. Now Castrol want £90.00 for six litres. Is Castrol indulging in restriction of sale by only supplying Jaguar dealers? Will not be purchasing any more Jaguars unless they change the service conditions. My car is 12 months old, covered 4500 miles, and they expect me to pay £90.00 for oil with the threat of removal of warranty.