Educated at
Marlborough College, Mainwaring was commissioned into the
23rd Regiment of Foot on 30 January 1878. He saw action in the
Third Anglo-Ashanti War in 1873, the
Third Anglo-Burmese War in 1885 and the Bhanio Mogoumg expedition in 1886 as well as the
Hazara expedition in 1891. He became commanding officer of the 2nd Battalion
Royal Welch Fusiliers, which he commanded in
Crete, for which service he was appointed a
Companion of the Order of St Michael and St George, and then took part in the
Second Boer War in 1899. He went on to serve as commander of the
23rd Regimental District from 1900 to 1906 and as General Officer Commanding
68th (2nd Welsh) Division from January 1915 to November 1915. ==Works==