Excellent. Ramsden is the man!
"Far more likely to have an uncommon manifestation of a common problem, than an uncommon problem" is a great way to put it. It sounds like he is right on top of it, you will be taken care of now. And "ouch" for your GP, when he gets that scathing letter!
I met a guy at our local ANA meeting last time, who joined us because he has Meniere's disease, not an AN. His symptoms were remarkably similar to our ANs; it is basically like having an AN, only without the tumor. I can't remember what treatments or medications he did, but he said it was well controlled now, with only very brief occasional flare ups.
So congratulations on getting somewhere with your mystery. Feel free to stick around on the forum, there are several non-AN members in the same boat, having similar symptoms without the actual tumor. The balance and hearing sections will still be quite relevant to you. We should really be the "ANs and all other wonky head causing diseases and mysterious head symptoms without a diagnosis" forum.
Best wishes,
Steve