Jumper's Knee and fencing

pretty sure I have patellar tendinopathy, though my GP is refusing to
diagnose it as anything at all.

I displaced my left patella when I was seventeen and walked with a stick for
a while. Since getting more seriously back into fencing (I'm twenty seven
now) I've had more and more pain from the patch just below my left kneecap,
feeling like bruising and stiffness, definitely worse with impact, but
noticably bad after fencing although there's little impact there, there is a
lot of stretching (Im right handed, fencing all three weapons).

Does anyone have any experience or advice? I'm not keen on taking a lot of
time out from fencing, but I also don't want to exascerbate it.

cheers

Gav