rear parking sensors

i am to fit parking sensors to the rear of my 2003 td5.
it looks straight forward.

has anyone done this/had experience.
finding an earth will be easy but what colour is the reverse light cable? guess i really only have a 50/50 chance its that or the fog. would make life easier if i knew before i started.

advice on positions would be good to. figured the sticky out bits and just on the curved ends next to the reverse/fog cluster.

reverse light is a green/brown wire, ecu, speaker etc normally fits behind the left hand rear lower trim (where the foldaway seats go)

been years since i done one, thats about all i can remember

thanks cd
busy weekend ahead with fitting these and the towbar.
bet you it rains.