Find Ancestors

I am trying to trace my great grandfather who gave his name as Ernest Charles Anthony Alouis' Walker. He was suppossed to have been born 3rd March 1890 in the Coventry area although I am not sure about this. He may have been brought up in a mining community. Family stories tell us he was a stable lad for the Duke of Norfolk at Arundel Castle, Sussex. He was in the Kings Royal Rifle Corps and served in India and attended the Delhi Durbar of 1911. He was in WW1 and served in France 1914-1916. He was at the first and second battles of Ypres and the battle of Loos. He was in the First Battalion of the Kings Royal Rifle Corps which was part of 6 Brigade 2nd Division. He was injured and sent to a rest camp on the Isle of Sheppey. it was here that he met my Great Grandmother Olive Constance Back. After he died in 1958 a story was told to his children that he and Olive never married and that they went to Brighton where he changed his name and they came back as Mr & Mrs Ernest Charles Walker. We have explored all avenues we can think of and have hit a brick wall. Can anybody help!