Had the car detailed and now when I back up I do not get the warning chimes

 

The miniature speaker is in the rear of the centre console - unlikely they've had that trim section removed?

Control unit is bolted across the LH corner of luggage compartment. Chance the harness connections have been disturbed?

You can download the Installation PDF from my MediaFire account:

Jaguar XK Series - Reversing Aid.pdf

The procedure naturally concentrates on measuring and cutting the sensor holes but it has all the important details you need for tracing and troubleshooting sensor or control box connections.

Graham