Evening all. I checked the bulbs and fuses and all were okay. I finally found the switch on the gear box. You can get to it from under the bonnet to the left of the battery. It was indeed green in colour.
What threw we was that it has three wires, not two, so kept ignoring this particular switch. Using a multi-meter I found that the middle wire was carrying the 12 volts. I bridged the left wire to the central, ignition on and hey presto, reverse lights were on
Thanks for all the help to get this far, all has been spot on...all I need now is some advice on where I can purchase a new switch from? Anyone got some advice? The part number on the switch was pa66-30gf