I think its good news, I borrowed a sports injury book and after a little read I have re diagnosed my knee issue. It is no longer tendonitis, my problem I think stems from a miss balance in my vastus medialis and my vastus lateralis. (Inner and outer quad muscle) this is causing my knee cap to be pulled out a little and so rub on the femur. The good part is that I can fix it by training. So if I strengthen the inner quad that will fix the imbalance and sort out the problem. All sounds very positive. It also sounds like cycling in the hills might help as I will have to stand in the pedals more and so work the inner muscle more. This feels much better than tendon trouble.
It’s a pity that we do not have a leg extension machine at work, that would have been very handy.