The Wolves Of Willoughby Chase - Joan Aiken

1832 - a period of English History that never happened. Good King James III is on the throne and the country is ravaged by wolves which have migrated through the newly-opened Channel Tunnel. When Sylvia and Bonnie (both orphans) fall into the hands of evil Miss Slighcarp, they must use all their wits to escape unscathed - for the governess is more cruel and merciless than the wolves that surround the great house of Willoughby Chase.