Sally with her twin brother Ben are the two main characters of the Beware of the Demon Headmaster book, a book, whilst still considered to be with the Demon Headmaster book series due to The Headmaster appearing in it, does not feature any of the members of SPLAT or any other character from the other books.

Within the book Sally is taking a class trip to Notley Castle whilst texting her sick brother, Ben, every hour who as he was to ill to come on the trip.