The pain has really gone off now. I had been swimming a lot, had a week off, went swimming yesterday and as I breaststoke kicked there was some pain so I'm wondering if that had something to do with it. I've also had a really sturdy knee support on which has definitely helped. Mmm... there is a physio round the corner, it does look slightly "new age" though...
I tried to do what you recommend but I've just moved house and have minimal furniture and there is nowhere I can lie back with my feet hanging off the floor. I've been sleeping on a thermarest for a month which has done wonders for my back but hasn't really helped the ankle as I lie on my front with my toes extended and when I wake up the first few steps are dubious and feels like my ankle is about to collapse, that goes off pretty quick though.