« Reply #8 on: Thursday 26 July 18 19:10 BST (UK) »
GRO website gives mmn (new since original post). Then check freebmd for marriage of the appropriate surnames - hopefully you'll find a Thomas Hennessey marrying a woman with the right surname to fit with the census rec found. Of course marriage may not have been in England or Wales in which case this won't work. Or mother may have been widowed which makes it more complicated.
Lots more online since 2011
ALLEN
BARR, BARRATT, BERRY, BRADLEY,BRAMLEY,BRISTOW,BROWN,BUGBIRD,BUTLER
CAIN,CARR,CHAPMAN,CHARLES,CH*LTON,CHESTER,COCKETT
COLLASON,COLLYER,CORKERY
DARLING, DENYER,DICKERSON,DOLLING,DURBAN
FARMER,FURNELL
GIBSON,GILES,GROOMBRIDGE
HALL,HAMBIDGE,HARMES,HART,HICKS,HILL,HOLLOWAY
JACKSON
K*AT*S
LANCASTER,LINTON
MCDONALD,MCFADEN,MEARS,MILLARD
NICOLAS,NOAK,NORTH
PARFIT,PORTER
RIPPINGALE,ROBINS
SEARLE,SPENCER,STEDHAM
TYLER,TILLY,TUCKWELL
WADE,WAGER,WALKER,WATSON,WEBB,WITHRINGTON,WOOD