Thanks all for the wishes etc.
Just back from GP and x-rays and scans.
Seems I did dislocate my knee but my accidental putting it back in saved a heap of trouble. It was just instinct. The swelling is comprehensive but R.I.C.E is helping. Its pretty bad looking.
I now have to have an MRI to see if there is cruciate ligament damage.
Unfortunately there is the possibility of a "Segond fracture" so will go on orthopaedic surgeon's advice. Best possible outcome is 2 weeks off the water, no windsurf, Sup etc, gutted

I now have some crutches and can drive OK after working my leg into the wagon so at least Im mobile as my wife doesnt drive

It happened at the far north western corner of Lake Munmorah after a whole bunch of us had been having a light but fun cruisey sail. Just went to shallow, own stupid fault

Thanks for all the support text's too!!
As the classic line goes "Not happy Jan" but in retrospect it couldve been a lot worse!!