Complex sentence: In 2007, the Duchess rented the neighbouring Dolphin House; a fire at Dolphin House in 2008 caused her to vacate the premises and move into Royal Lodge with her former husband.
Split into simpler sentences: In 2007, the Duchess rented the neighbouring Dolphin House. In 2008, a fire broke out at Dolphin House causing Sarah to vacate the premises and move into Royal Lodge with her former husband.