Went back to see the rheumatologist who diagnosed my fibro 18 months ago. I mentioned that my left leg and knee are painful and affecting my mobility but was putting it down toHughes or fibro. He examined me and said it looks like a knee problem and has sent me for an MRI. Salutary lesson for me - he said all too easy to think all my symptoms are down to what I already have rather than something new. So now waiting to see what the problem is and whether it can be fixed.