Replace the rear number plate bulb holders as the old ones had broken / melted. Think the previous own had put LEDs in that got way too hot.
What I assumed would be a 5 minute job took a little longer and was made a little tricky by a rear wipe that would not come off it's arm. However undoing the bolts holding the motor allowed me to wiggle it out the way and remove the tailgate handle for access.
Part number of the harness is 9483494 for anyone else doing it.