teeteringhead: your symptoms sound a lot like Benign Positional Vertigo caused by loose crystals in the semicircular canals of the inner ear.
Thanks
Meikleour.
That was suggested by the GP (random otoliths), but the consultant poo-poohed the idea (can't remember why). I've got the exercises from the GP - if it doesn't go away I'll give 'em a go. As we know from these pages, specialists aren't always right!