I have found the multifunction control module, I started removing all 5 connectors in turn and no difference to the drain.
I have looked again at the power seat adjustment, and when everything is off (key out) the power seat still works, and when I press the button the interior light goes on and off.
I disconnected the seat completely and there was no difference to the drain.
I disconnected the interior light and no difference to the drain
The only other thing I have noticed is that someone has removed both the footwell bulbs.
I also tried disconnecting every connector under under the steering column I could find in turn and there was no difference to the drain.
Is it possible that the modification that a previous owner did to turn off the seatbelt warning is an issue? Does anyone know how to reverse that modification?
The only other thing is that the drain varies between 3.5a & 3.9a, if the drain isn't present it goes back to 0.02a, if I open a door the drain is 0.84a, but I have never seen a drain of between 4.34a -.4.74a (ie: both the drain and an open door) which I guess means it is something to do with the central locking?
Of course I am now thinking of about 100 different possibilities, and I am not sure I have eliminated anything yet.