He will have had to provide identity on enlistment, either birth or baptism certificate, and if his mother had been unmarried at the time of his birth and had not subsequently married his father and changed the registration, which she would probably not realise she could legally do, he will have enlisted in his legal name not the name he had grown up with if say his mother had remarried but a step father had not legallt adopted him. What area of England was he from?