In reply to FesteringSore:
Had BPPV 10 years ago - triggered when I looked downwards with my head tilted slightly to one side. Symptoms: the world span, all concept of balance vanished and I'd find myself lying on the ground. GP was surprised I had no ear infection and no recent head trauma, and gave me Brandt-Daroff exercises to do twice a day. Said that should cure the condition within a couple of weeks, or I'd be stuck with it for good.
No change after 2 weeks, but condition was manageable once I figured out the exact head movement that triggered it. Resumed leading (muttering a mantra of "don't look down...") but became very wary of standing unroped on the edge of crags.
Continued the exercises just in case, and after 6 weeks, BPPV suddenly disappeared. Doesn't sound quite the same as your experience. Treatment with drugs and not sleeping lying down, were never mentioned. Hope you have a happy ending like me.
Post edited at 07:08