Complex sentence: While in Overstrand he stayed at the Mill House with miller Alfred Jermy and his daughter Louie, who became "the Maid of the Mill" in his articles about "Poppyland".
Split into simpler sentences: While in Overstrand he stayed at the Mill House with miller Alfred Jermy and his daughter Louie. Louie became "the Maid of the Mill" in his articles about "Poppyland".