I bought a 2.7 deisel on an 04 Plate, 3yrs ago. Over the first year I spent almost as much on repairs as I did on the purchase!
However, since then (last two years) the car has been faultless, returns 38+ mpg combined, and is a joy to drive.
My first jaguar was one of the original Mk 2s ~I'm in my 70s ~ and I always promised myself to buy another when I retired.
My advice to anyone looking to buy an S type: have deep pockets, buy the best model you can afford, put right anything that needs fixing, regular maintenance and enjoy.