Hi Alan, that does sound a little bit salty, but there could be a number of reasons for the higher cost. Did you get an estimate breakdown?
I suspect that there is little appetite amongst the dealer network to continue support for Jaguar as Jaguar Cars Ltd have not been very supportive of the dealerships, walking away from them in many cases. There may be also age related items that are not a normal part of the annual service such as auxiliary belts, etc.
You are probably fortunate that you have a number of dealerships in your locale, but as the warranty period is well past, you also have the option of finding a good local independent to undertake your work and build a relationship for the future.
I actually still have my own 2010 XKR under Jaguar Extended Warranty and spoke to them recently about the situation with the dealerships. They advised that as long as the work, such as servicing, is carried out to the correct procedure and interval, there would be no problem with the warranty conditions. They also said that an independent could undertake warranted repairs, provided they first got the go ahead from the warranty provider - same as a dealership would.
Keep the Forum informed as to how you progress as this is a topic of real interest at the moment.
N6 JMX