Got Ataxia and using a potion didn't work. Have searched and not found any previous info. Any help appreciated

A cure disease potion didn't work? Have you tried visiting a shrine (temple)? Or try talking to a vigilant of Stendarr. If those don't work, your game might be bugged.

Protip: drink a cure disease potion

No, neither healing potions nor cure poison will cure diseases

Best way is to go to a shrine which cures you from all diseases