Got my xray and waited a month and got an appointment with a consultant who said that there was no chance it was bone and its probably a cyst - he said it was like a bakers cyst, but only I had one on the inside of my knee as opposed to the back of the knee.
He also said that it was cause one of two ways;
either I put too much strain on the ligaments and it caused the cyst or;
I've damaged themeniscus cartilage (I think thats right) and the fluid seeped through the tear and caused the cyst - this is worse as it entails a longer rehabilitation.
so I'm waiting on an appointment for another scan to confirm it, - anMRI I think - to show more detail.
and Andy Murray still isn't good enough to beat federer!