Ok, no good, Checked the voltage going through the actual light socket and it registered as 0.01v for the front, back and numberplate light. so checked the exposed bits of the fuse as instructed and got over 12v. so it would seem there is power at the fuse box, but nothing between there and the lights themselves.
Finally I checked the resistance between the black earth (from the socket to the earth point) and it read 0.00ohms suggesting there is no resistance there i.e a break in the wire.

Anything else I can try? as I need the car for work, but dont want to get pulled by the plod for having not sidelights.