I am fairly sure from analysing the Birth Records that this is him. In which case he was born "Bertie Benton" but changed his name to Harry. The man who enlisted in the Militia was "Harry" and gives his father as Harry, sister as Maud and brother as William, and this is the "Bertie" in the 1901 census.
1888 Sep/Dec There is a Bertie Benton registered Sep/Dec 1888 for Orsett which includes Ockendon
1901 census at 277, Lyham Road, Lambeth

1911 census - the family, but not Harry are at 22 Horsford Road Brixton Hill S W

The record gives his father as Harry Benton, 87 New Park Rd, Brixton Hill, London, Sister (older) Maud and Brother (younger) William
1907 Jan enlisted aged 17 years, 9 months (implying a birth of about Apr 1889).
1907 Mar 14 "Transferred" - to Essex Regiment from Essex Militia.
