Hi all,
bit of an old thread but since I've just joined I thought i'd give you my answer to the above.
the diffs are white as said for convoy driving as white reflects well in IR and Visual spectrum, the idea was that with all lights off except the convoy light, this includes break lights.
The lead motor would have IR lamps on and his co-driver would use night vision goggles to guide the driver, the driver just used his normal vision.
This system is not used any more as the other side have access to night vision so can see your head lights.
There was also word that the right angle touches would be IR if you put the batteries in upside down, but I think that's a urban myth.
BTW will a NATO light switch pass an MOT as you could turn off your break lights, some soldiers may have done this if being tail gated, some civilians too I would have though.
M_O