Airospring's AS200 cushion hits the # 2 slot on Amazon.co.uk
AS100 - Airospring Seating Support Cushion
A very good cushion. It seemed thinner than I expected, but is very comfortable. As it does move, I have put a square of non-slip fabric under which helps.
I always expect to have a pain in my back at the end of a shift since I have used your cushion as a back rest as well as being so comfortable I dont have any back pain.