I am assuming that the physical bolt-on of the bar is quite straight forward, & that I don't have to remove the rear bumper?
no you dont need to remove anything, other than the upper right light cluster lens, to get to the electric plug loom.
look under the rear of your disco at the centre point.
immediately after the bumper are two vertical holes, these are pre tapped.
follow the chassis members toward the rear wheels and you will see the other two mounting points. these are horizontal through holes for the other bolts.
thats it four bolts.
easy
after reading another thread today, it would seem if there is no buzzer connected to your towbar electrics, then the dashboard trailer light will flash when indicating. my guess is the buzzer overrides the flash.
either complies with the latest regulations.