Parker purchased Shenstone Lodge near Lichfield, where he lived for the next 15 years. He returned to sea as captain of the third-rate HMS "Warspite" in 1827, and acted as senior officer off the coast of Greece in 1828. He was given command the yacht HMS "Prince Regent" in December 1828 and, having been promoted to rear-admiral on 22 July 1830, he was appointed second-in-command of the Channel Squadron, under Sir Edward Codrington, in April 1831. He was detached on an independent command on the Iberian Tagus River, hoisting his flag aboard the second-rate HMS "Asia", in September 1831 with a mission to protect British interests during the Portuguese Civil War. He was advanced to Knight Commander of the Order of the Bath on 16 July 1834.