In reply to petemcewen:
I had positional vertigo along with other vestibular symptoms after having labyrinthitis. I did vestibular retraining exercises for a while (which basically meant deliberately putting my head in positions that would induce the vertigo). They seemed to work well for getting rid of the positional vertigo. In my case, the goal wasn't to settle calcium carbonate crystals in my ear, because I didn't have BBPV. It was more to do with neurological retraining, I think. I definitley think they are worth doing and the fact that they feel so horrible is kind of the point. The conclusion I came to is that it's really important not to avoid the things that make you dizzy if you have a vestibular problem as it can make it worse.
You can get positional vertigo from a number of different conditions and the impression I got is that it's important to work out the underlying cause as treatments will differ. My experience of trying to get this kind of problem properly diagnosed and treated was, sadly, very negative. Luckily for me, my symptoms have almost totally gone away (expect for a bit of mild tinnitus when I'm knackered or very stressed) pretty much of their own accord. Slightly less luckily, it took just under two years (which adds to my suspicion that what I had was secondary hydrops). Anyway, I found this website to be very informative:
http://vestibular.org/
Good luck - I think I was fairly unlucky and it's quite common for these kinds of problems to go away fast.