In the novel One, Two, Buckle My Shoe, Lady Grant is a patient of the dental practice at 58 Queen Charlotte Street. She had an appointment with the dentist Mr Morley at 10.30 a.m. on the morning of the day when he was murdered.
According to Gladys Nevill, the secretary of the practice, Lady Grant is an elderly lady who lives at Lowndes Square.
In ITV's 1992 adaptation of the novel, the name "Lady Grant" is changed to "Lady Gregson". She does not appear in the episode in person but her name is mentioned by Gladys Nevill.