Complex sentence: George VI also paid Edward for Sandringham House and Balmoral Castle, which were Edward's personal property, inherited from his father, George V, and thus did not automatically pass to George VI on his accession.
Split into simpler sentences: George VI also paid Edward for Sandringham House and Balmoral Castle. These properties were Edward's personal property, inherited from his father, George V, and thus did not automatically pass to George VI on his accession.