American readers, have you heard of her? I imagine those of you who grew up speaking English in more colonial or British-ified locations will have. She writes series(es) of books for children: The Famous Five, The Secret Seven (both involving groups of children solving mysteries and having adventures) as well as the Mallory Towers series (about girls in a British boarding school).
I thought of them this morning when I left my daughter playing with two friends: Clara, Maisie and Pete (a girl). These sound like Blyton character names when you put them all together. The Thrilling Three: an adventure in the icy mulch.