[1] In the Second World War, Marreco was commissioned in the RNVR in 1940, serving as a Lieutenant Commander in the Fleet Air Arm until 1946.
[4] Marreco maintained homes at Porthall, a Georgian house near Lifford in County Donegal where he bred Charollais cattle, and in Shepherd Market in Mayfair in London.
He married Lady Ursula Manners, eldest daughter of the 9th Duke of Rutland and Kathleen Tennant, in 1943, but they divorced in 1948.
He reestablished his relationship with Lally Horstmann in 1951, joining her in South America and remaining with her until she died in August 1954, when he inherited part of her fortune.
[1] In 1954 while in Brazil for SG Warburg, Marreco met Regina (Gina) de Souza Coelho (b.
He married for a third time later that year to Anne Wignall (née Acland-Troyte), formerly the wife of the 5th Baron Ebury.