Ratcliffe resumed military service within the English army, being a captain of horse by 1624, and a lieutenant-colonel in 1625. On 8 September 1627, Ratcliffe was appointed a colonel in an invasion force under the command of George Villiers, Duke of Buckingham which attacked the Isle of Rhe in order to relieve the Siege of La Rochelle. He was killed during the Siege of Saint-Martin-de-Ré and the Duke was later forced to withdraw in defeat.