Hi and welcome
The modern Jaguar's seem heavy on discs and pads, because most are automatic, your allways on the brakes
new ones are not that expensive, try british car parts or sng barrat, both do genuine jaguar parts and aftermarkets parts at reasonable prices
also if your thinking of keeping the car long term, I can recomend "Krown Rust treatment", well recomended, I know loads of people who have had it done, even aluminium cars, as they can corrode worse than steel cars, also krown rust treatment is guaranteed http://krown.co.uk/uk/krown_application/Rust_treatment_process
cheers
Joe