Sister Boniface first appeared in "The Bride of Christ," a Season 1 episode of mystery series Father Brown, when the wine-making, Agatha Christie-reading nun helped Mark Williams' titular priest solve two murders.
The show takes place approximately 10 years after Sister Boniface's first appearance in Father Brown, which is set in the early 1950s. This series takes place in the early 1960s.
Sister Boniface operates a motor scooter with a sidecar, which is distinctly different from a moped, as mentioned elsewhere.
The name "Slaughter" comes from old English "slohtre", which means "muddy place" or "wet land". But of course Sister Boniface's fictional village being named Great Slaughter is a humorously open play on it being the site of a disproportionately high number of murders.
The convent where Sister Boniface is based is Princethorpe College, which lies just outside of the village of Princethorpe, which is very close to Marton, near Rugby in the county of Warwickshire, England. The chapel figures prominently in the Sister Boniface Mysteries and was designed by Peter Paul Pugin, son of the famous architect, Augustus Welby Northmore Pugin. Princethorpe College is a Catholic co-educational school for ages 11 through 18, i.e. 6th grade through 12th according to the U.S. system. The school was originally a convent but was acquired by the Irish branch of the Missionnaires du Sacré-Coeur (Missionaries of the Sacred Heart) in the 1960s, which converted it to a school and ran it up until 1998, when the first lay headmaster was appointed. Pupils who finish at Princethorpe regularly attend the Universities of Cambridge and Oxford, and other top institutions of higher education.