My x-ray showed no 'bonal abnormality'. And so the doctor eventually reached the grand summary: 'At the moment your knee's giving you jip.' Thanks for that.
Apparently I have a Prepatellar Bursitis: inflammation of the bursa (little joint cushion) over my kneecap. This quite possibly has nothing to do with running at all, and sometimes just comes along 'like a cold'. Running just makes it worse, and hurt a lot. There's no real way of remedying it, it seems, other than wait for it to go away, do a few leg stretchy things, ice it, take ibuprofen. This is quite crap. It doesn't even hurt. But if I run on it it'll probably get worse and won't repair. Frustrating, a lot.
It's nothing serious though, which is good : )
The Brighton Half is in 16 days, so I'm going to rest up a bit longer then see how it is and hopefully/maybe I'll still be able to run that. But mainly I just don't want to take any chances for the big marathon in April.
Thanks to everyone who has sponsored me so far!