Complex sentence: The estate was sold out of the Cotes family to Captain James Foster (1853-1927), who had previously leased the house and lived there many years, and was occupied as a private house until after the death of his surviving sister.
Split into simpler sentences: The estate was sold out of the Cotes family to Captain James Foster (1853-1927), who had previously leased the house and lived there many years. The hall continued to be occupied as a private house until after the death of his surviving sister.