It's shocking I was talking to a friend's mother a couple of weeks back who had been in really bad pain for a year from a knee injury. Her GP kept saying it would get better by itself and refused to refer her for an MRI. She went to visit her DD in the US and the daughter took one look at her and took her to her own family doctor, who took one look at her and sent her for an MRI, which revealed I forget what, exactly, but something that was definitely not going to fix itself but only needed a small operation. They had to pay, of course, but that wasn't so much the issue (although NHS should have provided it free) as being "allowed" to have the scan, which should have been done as soon as a few weeks had gone past with no improvement.
If there's anything, practically speaking, that we can do to help please say. Are there any private GPs near you who could do you a private referral? Supposedly BUPA run private GP services in Norwich, but looking at their website I don't think they do referrals for chronic conditions. Near me (and presumably in other areas) we have groups like MediClinic who offer private GP services that do include referrals. We just need to find something like that nearer you.