Thank you all for your interest and replies. I must admit I don't think it is my man. The information I have is from the birth certificate for his son Frederick James on 11 January 1851, registered by the mother in Hemingford Grey, Hunts, on 30 January 1851. Certificate clearly states "Private in 1st Batal. of Grenadier Guards". His wife, Ann, is staying with her son at her parents house at the time of the 1851 census.