Shorn, the list of problems sound like our Mercury Sable; in the 15 years of owning my 1984 XJ-6 (another pristine example like John Farrington's, and no, I am not selling mine either), I have never had those kinds of problems, and you all know what they always say about Jaguar's electricals, not true in my car, it is absolutely reliable mechanically, electrically, you name it, however it is not a Toyota Corolla in gas mileage, nor do I expect it to be, it's a Jaguar. And yes, I have replaced the front brake rotors and pads, and I change the fuel filter and oil and filter when needed, belts too, and a/c compressor once. same as in any other car I've ever had.
What is curious is that both my Jags are not Trailer Queens, but I drive them long distances, from Tennessee to California or Florida or Pennsylvania, at an average 80mph. I've yet to have a failure that left me stranded on the road, as in "Tow Truck Time", unless you count a flat tire as a failure. I always say: "if it's not worth driving long distances, it's not worth having".
On the subject of cost to repair the front end in your car, (sounds more like rebuilding it), I may be ignorant of what's happening in the Jaguar repair business, because I do my own repairs, and then I don't have many repairs to do, usually things that I can fix by asking others for help, like adjusting the carbs in my '65 S type because it was dieseling. I got the answers I needed right here in this forum, a little tinkering, problem solved. (the Mercury Sable is a problem, but I usually get it fixed researching the internet). I still think you need to get other opinions on the supposed failure of the front end in your car at 45K miles.