By the 1861 census he appears to be this married man
1861 census RG9 199 folio 26 18 St? John P? Rd Clerkenwell Middlesex Henry G Hamilton 22 Head Married Watchmaker employing 1 boy Calcutta E Indies (1871 census - birthplace at sea Bay of Bengal, 1881 the ship Repulse Bay of Bengal) Catherine E Hamilton 25 Wife Married Camberwell Surrey Henry Hamilton 3 Son Clerkenwell Middlesex
Marriages Dec 1859 Hamilton Henry George Whitechapel 1c 791 Poole Catherine Elizabeth Whitechapel 1c 791
HENRY GEORGE HAMILTON CATHERINE ELIZABETH POOLE Marriage: 06 NOV 1859 Spitalfields Christ Church, Stepney, London
Marriages Dec 1865 Hamilton Henry George Clerkenwell 1b 1096 Pyne Mary Clerkenwell 1b 1096
Either of Henry George's marriages would give details of his father.
Surrey History Centre has the deposited committe minute books of the Royal Asylum of St Ann's Society
Committe minute books of the Royal Asylum of St Ann's Society contain
'Committee meetings were usually held every month, and the girls and boys were 'examined' at alternate meetings; there is no indication as to the manner of the examination. The names of those pupils admitted to the school, and discharged or warned for non-attendance are recorded, together with those apprenticed and to whom...'
Surrey History Centre may also know of any other records that have survived for the asylum.