Archie - I also have had no luck matching a participant in the Second Boer War with the information you have given. However, moving on to Ancestry & Find My Past more generally and with the help of a Public Member Tree on Ancestry I appear to have found a perfect fit – here are some of the crucial details of his life which you may already be aware of:
Born 29th June 1873, Doncaster.
Married 5th November 1899 to Hannah Evans in Thornaby-on-Tees – in 1899 Thornaby was in the Middlesbrough Registration District for Births, Deaths & Marriages.
31st March 1901 Census – Harry & Hannah were living at 35 Windsor Road, Stockton-on-Tees with their 2 week old son George and Harry’s younger sister & brother were living with them. Harry was a hairdresser and his younger brother Frank a pawnbroker’s assistant.
The 1911 & 1921 Censuses show Harry & Hannah had a second son named Fred who was born 1 years and 5 months after George.
So if this Harry Dutton did serve in the Second Boer War it was either early on or late on. Coupling that with the photo uniform which suggests a member of the Imperial Yeomanry (IY) – the IY went out in three waves – first Jan-Apr 1900, the second a year later and the third another year later. I think being part of either of the first two waves would probably compromise him being the biological father of his sons. If he went out third wave his participation in the war would have been minimal and some of the third wave actually arrived in South Africa after the war had ended on 31st May 1902.
Harry & Hannah were still alive in September 1939 when they appeared on the 1939 Register living at 27 Bon Lea Terrace, Thornaby-on-Tees and Harry was still a hairdresser with “master” added in brackets.
The Public Family Tree says he passed away in 1953 but i have not personally verified this.