That looks possible, Merry.
John's wood engraver son, Thomas, is recorded as being married in the 1861 census. John isn't with Thomas and his wife. I reckon Thomas's wife, Elizabeth, from Tring, the niece in the 1851 censes, are the same person.
Hackney
Thomas Seabrook, head, 34, journeyman engraver on wood, b Middlesex, Aldgate
Elizabeth Seabrook, wife, 38, born Herts, Tring
http://interactive.ancestry.co.uk/87...l=ReturnRecord