This one was irritating me...
I am not sure if the wiring route I took was wrong, the wiring had got snagged behind the rear panel or something completely unrelated however the rear fog lamp wiring does not reach the spade connectors in the fog lamp.
Only option was to carefully drill a new hole in the rear panel (being fully conscious there is a fuel tank at behind it) and poke the wire through the new hole. The new position for the hole actually produced more slack in the wiring so re-routing the wire did not ultimately prove to be too difficult and thus dismissed the initial idea the wiring had got snagged when the rear panel went on as it was free and easy to relocate to the new hole...