William Henry Fentiman's mother was Mary Caroline - listed as unmarried in 1861 (William age 8) and unmarried in 1871 (William age 18). The aggravated assault is definately the right man as the name, occupation and address all match perfectly. There are plenty with the same name (not necessarily with the Henry) for various offences, workhouses, asylums or a Court Martial in April 1879 and later a deserter in 1880 ? Being a deserter would explain his aparent dissapearance as he would probably be keeping a low profile and might even have changed his name ! It's looking like this one might be a dead end.