As promised, an update. I have an ultrasound appointment on 16th September. Not with the doctor I wanted, who is unfortunately not available for the foreseeable future. I hope the suggested doctor is as handy with the ultrasound machine. My referral letter states Ultrasound +/- Diagnostic local anaesthetic injection. I'll be another £500 lighter afterwards, but this is really the last hope I have of any kind of diagnosis I think. I've been doing half an hour of exercises 4-5 times a week, as prescribed, providing a little focus to try and stop myself unravelling, which isn't easy at the moment.
Unlikely I'll have much to say before 16th, so take care until then.