Mr Jilks, the only one i found is a James Jilks b.12 July 1857, he served as a Dockyard Police Constable at Gosport/Portsmouth Dockyrads. He is on the 1881 census as a constable address Gosport. He is on other census but addresses are always Gosport/Alverstoke. He marries Charlotte Crassweller in 1885 Gosport. The 1911 and 1939 census list him at 75 Avenue Road Alverstoke, Rtd Police Constable.
He dies 1944 in Gosport District.
Born 1857 and in the Police in 1881 age 24, it would give him very little chance of military service not to say he could have been a boy soldier at 14+.