Thanks for that. I do run with a short stride, along the lines of Chi running.
My knees have been destroyed by many many silly things I have done over the years. It's also something I inherited from my father - his knees are shocking too!
In most cases for me the injuries flare up due to really tight quads and calves. So I just need to stretch a lot after the run and in between the runs and I should come right.
I should be ok to run again tomorrow, but I'll see how I feel.