Back again,
I got it to work, just in reverse. Now I have a green light on my dash when it's not in 4wd and this goes off when you are. Not a problem because at least now I have an indication and it's all good. To do this I cut one of the wires that comes out of the switch and made a triple connection which was the two halves of the wire and the live of the light. The earth of the light went off to an earth on one of the stereo screws.
The back of the 4wd switch has five wires going into it and the one I cut is the one that's by itself on the row that has three wires in it.
Hopefully my pictures worked and you can see what I mean. The black wire from the light is the live and the white is the one going off to earth.
edit.. Yay ! I got photos to upload !
ps. To test if you have the right wire before you cut it ( in case they are in a different position ) just earth the light and poke the wire into the connections at the back of the switch to see if it lights up and goes off when you hit 4wd.