[5] Metcalfe was mentioned in dispatches, reported in the London Gazette on 15 August 1917, and ten days later came notice that he had been awarded the Military Cross for distinguished service in Mesopotamia.

Metcalfe first met the future Edward VIII when, as Prince of Wales, he was touring India in 1922.

Edward was impressed with Metcalfe's knowledge of horses and made him a member of his personal staff, appointing him an aide de camp; he subsequently accompanied the prince on his tour of Japan.

With his wife, he attended meetings of the Oswald Mosley organization in the January Club,[13] and, in May 1934, a dinner at London's Savoy Hotel of the British Fascist Blackshirts,[14] of which he was a member.

[15] After the king abdicated on 11 December 1936 and became the Duke of Windsor, Metcalfe was best man at his wedding in France to Wallis Simpson on 3 June 1937.

"[18] On 10 August 1940, Metcalfe was commissioned as a pilot officer into the Administrative and Special Duties Branch of the Royal Air Force.

Metcalfe and his wife, Alexandra, purchased a grand country house, Little Compton Manor, in 1939 near Moreton-in-Marsh, Gloucestershire.

Lee spent many respite weekends at the Manor until the D-Day Invasion in June 1944, and also entertained many military and diplomatic visitors there, recouping from the crushing responsibilities of managing the largest logistical operation in the history of the world.