Edit- Sorry forget the thoughts below - this Henry appears to still be living with his parents in 1881
Just as a thought when you have the certificate - I did find this family in 1861 living at East Horrington, St Cuthbert In Wells Somerset with a son Henry born in Wells. There is a birth in the FreeBMD index of a Charles Henry Seaward in 1857 in Wells which may be too early but worth considering.
BROWN, James 30 1831 Agricultural Labourer b Wells, Somerset
BROWN, Elizabeth Wife 31 b Uplyme, Devon
SEAWARD, Keturah Daughter In Law 10 Uplyme, Devon
SEAWARD, Marian Daughter 6 Wells, Somerset
BROWN, Henry Son 4 Wells, Somerset
BROWN, Thomas Son 4 months b Wells, Somerset
RG09 piece 1663 folio 48 page 5
There is a christening on Family Search of a Charles Henry Brown on 1 Feb 1857 at St. Cuthbert, Wells with parents James and Elizabeth Brown.
There is a possible marriage of a James Brown to an Elizabeth Seaward in Wells in the FreeBMD index in March qtr 1859 in the Wells Reg District Vol 5c Page 923 which could be the couples marriage, after Henry's birth.
Kay