Enter the Royal Spyness series featuring Lady Georgianna Rannoch, 34th in line to the throne but penniless after the Great Depression (it's 1933) has left her family broke, and with the huge expenses of an estate to keep up. She's not married, and her brother has a difficult time supporting her on the estate, so she heads to their home in London and tries to either find a husband or find some way to make money. She starts off opening her own cleaning service, but finds herself involved in mystery after mystery. Plus, the Queen keeps giving her secret assignments, some of which wind up being life-threatening.
I'm not a huge mystery fan, but I really enjoy the Royal Spyness series, and find Bowen's descriptions of 1930's London vivid. They are fun entertaining fluff books that fill the spaces when I need a break between more challenging books (like Thomas Penn's The Winter King about Henry VII, which I'm on now...laborious, but oh so worth it!).