I found the reverse light switch in the engine bay under the bonnet. It is on the right hand side and on top of the gearbox. It is directly under the air duct. The plug is white plastic and just clips off.
If you need to remove the reverse light switch then just un screw it. It is possible to test it whilst its fitted. Use a multimeter on resistance setting and test across the 2 terminals on the switch, you should get an open circuit. Put the gear in reverse and you should get a closed circuit. This can be done using a test lamp also. If the switch opens & closes then it is Ok, if not the switch is faulty and needs changing. A new switch can be had for under a tenner!
Evets, December 2008