James Leonardi Mm

hi everyone
im looking to find my grandfather james leonardi mm who served in france and won the military medal in france i no he was a lewis gunner and he was in THE YORK AND LANKS reg army number 19084 and i would like to no more about it ,ive been on numerous genealogy sites and ive got his medal card and ive seen the citation in the london gazette but im still struggling to find out more if anyone can help me i would be most gratefull
best regards brian