I believe even in the UK it's possible to pay for private treatment, right? I would do that. I'd find the best infectious disease or orthopedic doctor who takes private patients and get an appointment.
What could be going on is that your body is fighting the infection somewhat successfully. That could explain some of the issues coming and going, that it jumps out and makes you sick, then your immune system fights it back down to wherever the reservoir is, then it breaks out again.
And yes, the infection probably is why your neck is spasmed. That or the pure stress at going through all this.
I have paid for private consultations only to find I see the same guy I saw on the NHS. The one out of town will be private, only snag is I still need a GP referral which they don't send off! It's a farce. The out of town place are aware of all my concerns re infection etc, and I'm hoping they will be more thorough. I have been emailing them and they are just needing that off my doc. Because osteomyelitis is so uncommon everyone just seems to shrug the idea off. It will be an orthopedic surgeon I see in a reputable spinal unit so I hope he will have a clue.
I agree with you entirely about my body fighting it as it flares, then it goes dormant again. Do you want me to keep you informed if I find anything out eventually? You have been a big help and thanks so much again.