Kathleen Mary Pearson was the daughter of a physician and was raised in a Georgian house at the end of the High Street in Leighton Buzzard. The house now forms part of Leighton Middle School, known within the school as The Old House, and was reportedly the setting of her novel "The Borrowers". She married Robert Charles Norton on 4 September 1927 and had four children, two boys and two girls; her son, also named Robert Norton, became a printer and Microsoft executive. Her second husband was Lionel Bonsey, whom she married in 1970.