Coming home from shopping yesterday afternoon, realised the tailgate window was not shutting correctly, and instead of sliding up behind the roof, was actually hitting it and stopping.
Upon investigation I found that the glass was kinda loose, waggling backwards and forwards.
Today I have completely stripped out the tailgate window, motor and runners, to find that the aluminium clamps that hold the window have two small white plastic U shaped clips that it actually runs on, and one off each side had fallen out and were laid in the bottom of the door.
5 minutes of gentle persuasion had the clips back in place, but while everything was accessible I have spray greased the runners, copper slipped the bolts, contact cleaned the motor plug and refitted everything.
The rubbish foam membrane was replaced with a 120 litre heavy duty bin bag (which happened to be just the right size with the bottom cut off and then opened flat so it was actually double skinned!) and considerably more gaffer tape than was probably necessary
All in all a productive day