I went for a tiny little jog this morning with Mike. No good unfortunately - pain fairly soon, do I stopped. I had a session with Jamie who feels it's a bunch of muscles (perhaps mainly perineum longus) around the top of my fibula. I think it'll take a bit of work and time.
I've decided to try to make a virtue of all thus and use the time off as my annual break. But to be honest, I'm climbing the walls that I'm not racing tomorrow.