Just wanted to add that the serious mood issues are ongoing, and my GP is awaiting the advice of a psychiatrist. I have the letters that mention all this, but the only time she mentions the severity of my anxiety and suicidal thoughts is alongside the exercise comment!
You seem to have a good understanding about producing supporting evidence, and I appreciate your problem. Only you can decide which way to jump on this one.
Sorry not to be able to give more precise advice, Catherine
Nothing on this board constitutes legal advice - always consult a professional about specific problems