George Denis Carroll

Query: I am interested in sharing information about my great-grandfather, George Denis Carroll. He was born about 1853 and joined the British Army ( 70th Regiment of Foot) at the army depot in Mulingar Westmeath as a private on 22 July 1870. His father was MIchael Carroll. Two years later he was in India with the army serving there until about 1882. He never returned home, but married an Irish-Indian girl, Margaret McLoughlin, and had 6 children with her while working as a railway engine driver. He died in Allahabad in 1900. His only son was my grandfather. I know a great deal about his life in India and his decendants, but only what I have stated of his life and family in Ireland. It seems likely that he came from Westmeath. Please can you advise me how best I can try to find out more? I live in Canada