Hence "Doolallytap!", a form of insanity allegedly brought on by being held at Deolali waiting for a ship to Blighty.
Every day's a school day! Thanks LangleyB, that's cleared up a question I've had in mind for a long time. We know two Sallys who live locally.
To differentiate between them, we call one "Pally Sally" and the other one "Doolally Sally". We don't use their surnames because they're both divorced but "otherwise occupied". I always wondered about the origins of the name of the latter species.