The regiment was stationed in South Africa, and Rimington's first active service was the Warren Expedition in 1884 to recapture the United States of Stellaland.

[4] That year, he married Agnes Cunningham; they had one son, Reginald, who followed his father into the 6th Dragoons and later the Royal Tank Regiment.

The focus of the operations in the Orange Free State then shifted to irregular guerrilla warfare, and Rimington's troopers saw heavy service here until the end of the year.

[6] Rimington returned to the 6th Dragoons, following a promotion to lieutenant-colonel on 29 September 1900, to take command of the regiment, and fought with them through the remainder of the war.

[11] The war ended with the Peace of Vereeniging in early June 1902, and Rimington returned home in the SS Tagus, arriving at Southampton in July.

[12] In his last despatch as Commander-in-Chief in South Africa, dated 23 June 1902, Lord Kitchener described him the following way: Brevet Colonel M. F. Rimington is a leader of mounted troops, who is particularly well qualified for the conduct of special and independent raids or enterprises.

[8]He received the actual decoration of CB after his return home, from King Edward VII at Buckingham Palace on 24 October 1902.

[17] He was appointed a Commander of the Royal Victorian Order (CVO) on 16 December 1911 at which time he was Inspector-General of Cavalry in India.

[18] Following the disbandment of the corps, Rimington was given command of a reserve centre in the United Kingdom, from April 1916 to January 1918, and retired from the Army in 1919.