I want to know the author/ess and publisher of the children`s book, `The Little Left-Over Witch`` please.?

This lovely tale is of a young witch on Hallowe`en. Her Elders are visiting Earth from wherever, and to teach her manners/to mend her ways, they abandon her for a year. They leave her in the high branches of a bare tree, outside the bedroom window of a girl her own age who takes her in. It`s a paperbacked book, with some black & white illustrations. Can anyone remember it and help? I last had it around 1990.All leads appreciated.ThankYou.