In 1949, Cazalet and Mildmay stayed at Windsor Castle as guests of Her Majesty Queen Elizabeth. It was during their stay that they persuaded the Queen to buy a steeplechaser, which Cazalet would train. An early success was Manicou, who won the King George VI Chase at Kempton Park Racecourse in 1950. Another of the Queen's horses trained by Cazalet was Monaveen, jointly owned with Princess Elizabeth. Following Mildmay's death in May 1950, Cazalet inherited the horses owned by Mildmay and £10,000.
