Well.. i decided to have a look while on my 10min break at work the other day. I took a piece of cardboard and crawled on my back under the rear of the car.. The pin/arm is still attached, and I gave it a bit of the old 'in/out, in/out'

lol
turned the engine on and tested the dif lock and the rear now seems to be working.

but it is very oily around the rubber boot, there seems to be a little screwed type cir clip thingy on it, and its snapped in half. Is it suppose to stop oil escaping from the diff?