As per the below post. Well, I looked her up, and saw that, as well as having written a number of other books, including The Poodle Room, Duck's Back and Men Are So Helpless, and being a member of the International Sportsmen's Club in Grosvenor Square, her original name was Maugham.
A Maugham author early in the 20th century? Worth investigating, I think you will agree. It transpires that Kate ('Kitty') was Somerset Maugham's favourite niece, and he was influential in the publishing of her first book. Her husband, Robert Charles Bruce (or 'Robert the Bruce' as I have taken to thinking of him) was a stockbroking collector of jade and porcelain.
Her sister, Diana Julia Maugham Marr-Johnston was another author (for instance: Goodnight Pelican, 1957), and she was about the only Maugham who didn't mind Maugham's obnoxious secretary, Gerald Haxton. Her husband Kenneth did mind Haxton - in fact he thought Haxton was evil and called him 'The Black Bishop', which is quite a cool nickname.
Brother Robin (real name Robert) had a pretty exciting life; sister Honor was a pushy portrait painter. Their dad was Lord Chancellor. Now you know.