It comes through under ther boot floor, if you lift the boot floor lid, and the large centre wheel cover, you will see a black polystyrene surround. This is stuck down with a little adhesive, and when pulled up you reveal your grommet from your abs cable - LH for Rear LH sensor RH for RH. I took all the side panels, seat etc before coming to this solution.
Dominic Tattersall, February 2011