Complex sentence: The estate was finally sold by the Du Cane family to Sir William Boulton, 1st Baronet in 1919, who then sold it to The Plessey Company in 1947.
Split into simpler sentences: The estate was finally sold by the Du Cane family to Sir William Boulton, 1st Baronet in 1919. The property was sold it to The Plessey Company in 1947.