Hi, I know this is a very old post but if you are still looking, I used to live in london and Doctor Saadi Doha at the Lordship Lane Medical Practice in East Dulwich is fantastic. He helped me get my diagnosis and was very collaborative with me in terms of testing different functions.
good luck

Or try pain management

You need a different doctor. Don't give up. Keep trying. Try an internist.

I have same problem with my terrible Dr's. Back Dr and Rhumatologist diagnosed me but said PC Dr.s treat it, my PC Doctors laughed at it, and don't believe it's real, saying there is no test to confirm it. Luckily I'm on Gabapentin which helps alot. But I'm on disability unable to work due to pain.