Uncovered him for the first time in about 3 weeks, emptied the 1/2 full dehumidifier.
Depressurised the rear (already down on the stops), then found the big jack wouldn't go under now, so ran him and pumped up enough to get the jack in and then depressurised again.
Got the wheels off the back, followed by the arch liners and about 8lbs of mud and crap. Brushed everything clean, tried to paint it where necessary but it is a bit chilly for that. Will Lanoguard it on reassembly.
Looked at how to get the rear airbags off but it looks a bitch, especially with rusted out top clips and ones at the bottom that seem to have been fitted and then bent over.
I'm guessing it will be chisel the bottom mount off the axle and break the pins, like it was with the front bags, but not doing that until I have trawled the forum to check on getting the top out without damaging myself or anything else.