Thanks everyone for your replies. I spent some time on all fours last night while watching TV, will do it again tonight, and I'm making sure I'm leaning forward whenever I sit down. Alan, I've kind of treated the swelling as the kind you get when you're flying long distances, so have already been doing exercises to increase circulation - good to know I'm on the right track! The next few days are supposed to be cooler so hopefully that'll help a bit.

Cheers