Birdbomb, I don't have an answer for you, not having either RA or epilepsy, though I do have carpal tunnel. I just wanted to acknowledge having read your post. You raised an interesting question, and I'll be watching with interest to see what answers you get.
You seem to be dealing with your problems with dignity. I can sure sympathize with your feelings of being beyond anger when they finally got around to finding the diagnosis. Pain is not good as a close and constant companion! And then to have been told it was all in your head! Sometimes you wonder where the doctors have their heads!?!
Hugs,