This gentleman appears to be a relative by marriage, so is not really a Hague Family relative, but he gave his life in the First World War, so I wanted to remember him. My great-uncle John Coaten Hague married Ellen Haddon in 1914, almost certainly a sister of William Partridge Haddon and Henry William Haddon.
A 1901 census record suggests his parents may have been James E Haddon and Mary unknown (but see CWG record linkied to below). He had sisters Edith and probably Ellen.
The census record below does not record his younger brother (by one year) William Henry. There was another William P Haddon born at around the same time, who survived the war, and my record as the source for my William Partridge Haddon census may therefore be in error. Or Henry William and William Partridge may not have been brothers at all.
There is a Commonwealth War Graves Commission record for this man.