Have you tried getting that information from previous and following Census years? (Apart from Witnesses of course)

This looks like the married couple in the 1881 census.
RG11/Piece 507 Folio 110 Page 23 in London - Poplar @ 41, Canton Street (sharing a house)
John B. Reading 29 Head born
Ramsgate Kent: a Mariner
Ann E. Reading 27 Wife born Norfolk, Yarmouth
so, going back to the 1861 census for example could well find them with their respective parents.
I'm limited on time today, so here's John B (did they name a Sloop after him?

) with his parents Daniel & Johanna in Ramsgate 1861 census:
RG 9/Piece 536 Folio 39 Page 20 Ramsgate @ ?? Place ?
Daniel, born c1807 in Ramsgate was a Master Mariner
Johanna born c1815 in Deal.
John has siblings ..... let me know if you want the entry fully transcribed?