In parallel to the squats I was also seeing the physio for regular massage and acupuncture of specific trigger points in my quad muscles (see other post) - which proved very effective in reducing stiffness and some of the minor symptoms.
Progress was very good for the first three week. I saw a good reduction in symptoms and was building up the squats well. But then it all started to go wrong, increases in discomfort turning into a running battle by which I kept laying off the squats because of a flare-up, restarting them only to see it flare up again and so on. By Christmas I had to accept I was (apart from benefit obtained from the massage sessions) not really getting anywhere. from reading this blog and other discussions it looks likely that my rate of increase was way too high. So the plan now is to rest for a couple of days and then restart doing only one session a day and only adding one squat a day - let's see how that goes....