Colour wire for reverse sensors

Update : Right all done and didn't even take the bumper off ,just need to know which wire to tap into on which side and jobs a good'n (y)
 
I'm not sure if Ford were consistent with wire colours for the rear lights as my USA ones (which came with UK looms) used a different colour scheme from my originals. Best thing to do is remove one of the rear lights, check the wire colour to the reverse bulb and tap off the same colour wire inside the boot or whereever it's convenient to join the sensor circuit.
 
Update on Update: Worked out which wire to tap into on advise from Flamenco ,so that's it all working , first mod now complete :)