Rear number plate light query

[fergus]

On my 1998 SLR, I have two bulbs in the rear number plate light holder, seemingly on separate circuits. As I don't have a circuit diagram to hand, would anyone be able to shed any light on what these may be (other than one circuit being part of the dipped lights circuit)?

I can't recall exactly what colours the wires were going to the two circuits, but from memory, there were green/black, red and black wires involved.

thanks