If your B12 is below 800, it may not be "fine." especially if you have symptoms of a deficiency.
Do you live in the UK? There are other MGers who do. Maybe they could help you to find a good neuro.
I'm glad to help, Caprice. I know exactly what it's like to be on the receiving end of less than adequate treatment.
It's a real shock to the system when the profession you thought was supposed to be helpful ends up questioning you. Don't let it get to you! It has, unfortunately, happened to a lot of patients.
High blood pressure can be dangerous. It can have adverse effects on the heart, brain, and kidneys. It's good they are doing something for it. It would have been better if they had figured out what was causing it.
Just get yourself some better doctors. Whatever is going on (and it could be more than one thing), you need some help and soon!
In the meantime, take extra special good care of yourself! Watch a good movie, eat great food, or take lots of naps!

Annie