Well as they say that was a long time between drinks!
Well playing badminton is over, the long battle with the knee is over and the knee won. In the end my physio offered me the choice of walking or carrying on playing badminton. But on the plus side she did introduce me to the rowing machine. I don't think she planned for me to work so hard at it, but that is one of the draw backs of being competitive, if you take out one way of being competitive you are likely to find another.