Harry was born on 17th October 1879 in Winchester, Hampshire possibly at number 8 Edgar Road, Winchester, to parents of the then Lieutenant-Colonel Samuel Barrett Miles of the Bombay Staff Corps and Ellen Kay and baptised at St. Bartholomew-Hyde's Church in Winchester on 20th November 1879.
He was again recorded at the address during the 1881 census with his mother, his Aunt being head of the household.
Harry joined the RMLI as a 2nd Lieutenant on 1st September 1898 and began his training at the Royal Naval College from 30th September 1898 to 31st July 1899 reaching Lieutenant 1st July 1899. He transferred to the Plymouth Division on 1st August 1899 for almost a year, moving to HMS Cambridge (a Gunnery Training School) on 10th July 1900. 12 days were spent attached to Plymouth Division before Harry was posted to HMS Royal Sovereign on 31st August 1900, a 1st Class Battleship. It was stationed in the Grand Harbour, Malta in the Mediterranean, during the 1901 census, Harry noted aged 21. He served from May 1903 to March 1909 on HM Ships Minerva, Europa and Juno, separated by interludes at Plymouth and Portsmouth Divisions.
Despite several remarks on his records from superior officers reporting he was "a good officer but somewhat slow" or "an officer who does his best but is not very intelligent", he persevered and passed the required exams to become Captain, failing in Military Law on the first attempt. Harry advanced to Captain on 2nd October 1908, and was recorded as such on the next census of 1911, aboard HMS Hampshire, stationed at Portsmouth.
If his intelligence was slightly lacking he was remarked at being very good at drawing.
Harry joined the Vanguard on 4th January 1913, seeing naval action at the Battle of Jutland in 1916 and passed his examination to become a Major in December 1916. His service earned him the Star, Victory and British medals.
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1881, 1901 & 1911 England Census - Ancestry.com
Linen Hall Library; Belfast, Northern Ireland; Periodicals & Newspapers, Irish & Reference
England, Select Births and Christenings, 1538-1975 - Ancestry.com
The National Archives of the UK; Admiralty and predecessors: Service Registers and Registers of Deaths and Injuries. Registers of Reports of Deaths
UK, British Army Lists, 1882-1962
Royal Naval Officers' Service Records Index, 1756-1931
England & Wales, National Probate Calendar (Index of Wills and Administrations), 1858-1966, 1973-1995
image credit - Royal Marines Museum