Looks like diagram 4b is the one you need.

So:
Red/Brown and Yellow/Brown aren't used at all so tape them up out of the way.
Red/blue and yellow/blue both go to permanent earth.

Yellow/grey needs to be spliced into the unlocking "ground" wire in the car (can't remember the colour off the top of my head.

Red/grey needs to be spliced into the locking ground.

Once you've done that it should all work.