I'm thinking of putting aftermarket parking sensors to my 1997 XK8 Convertible. I'm so used to all the warnings and camera on my current BMW, I find reversing the Jag very tedious!
I found one that fits behind the bumper from Parking Dynamics which requires no holes etc. as I don't want to alter the looks of the car in any way. I would be interested to hear from anyone who has fitted something like this. Would make a good winter project if they are any good.
I've got one fitted on the front of my XK8, Jaguar having kindly fitted a standard system to the rear, and it's OK. It's not as precise as the ultrasonic type, but it does avoid the disfigurement aspect, particularly on the front bumper of an XK8.
And if having fitted it you don't like it, it's easily removed without leaving any scars!
I fitted one that goes around the number plate on my old X300. Ok it only has 2 sensors on it, at either side of the number plate, but it worked well and was easy to fit, splicing it into the reverse lamp wire. I am pretty sure you can still get them, have a look on eBay.