Went to the chiro again today - the usual manipulations produced the usual cacophony of slightly disturbing sounds but I did (again) feel a lot better for it. To help me maintain posture when I sit (my worst time for both slumping and for favouring my right hip), I now have a large circular plastic air-filled pillow to sit on. It makes me sit upright because is if I move to either side, I slide off it. I haven't got to use it much yet but it certainly makes me aware of my posture.