Moondial by Helen Cresswell

Description

A classic story of time travel, ghosts and friendship. Even before she came to Belton, Minty Cane had known that she was a witch, or something very like it . .  Minty is the kind of girl who notices things. Pockets of cold air on a stairway.   Cries on the wind. Ghosts. On night-time jaunts from the house where she’s staying while her mother recovers from an accident, Minty stumbles upon a moondial which takes her back in time.  She finds Tom, a sickly kitchen boy, and Sarah, a girl with a birthmark who is only allowed out at night because her family think she has the mark of the devil . . .  Can Minty save her friends, or will she get stuck in the past . . .?  304pp

Helen Cresswell (1934-2005) was born in Nottinghamshire and lived all her life in the county.  This title was originally published in 1987.