Goodbye, Ms. Chips (Large print, Hardcover, large type edition)

"Ellie, the headmistress wants to see you."
Words to strike terror in the heart of any inmate of St. Roberta's boarding school who has failed to turn in her Latin prep, left out London on a map drawn of England, or prowled the ruins of the medieval abbey at dead of night. Ellie has been guilty of all these sins and more.
Fortunately, however, she is no longer a pudgy, insecure adolescent but a happily married interior designer with three lively children and a beautiful home by the sea. The only cloud in the sky on this lovely day in June is the message relayed by her friend Dorcas, who became games mistress at St. Roberta's when the former coach, Ms. Chips, retired. Having heard of Ellie's success as an amateur detective, the headmistress, Mrs. Battle, wants Ellie to come and find out who has stolen the Loverly sports trophy and is seeking to bring embarrassment to the school.
Her less than rosy memories of St. Roberta's notwithstanding, Ellie cannot refuse Dorcas's entreaties and finds herself in the thick of boarding school life, where an apparent schoolgirl prank soon gives way to murder.