Your man David had had his children baptized non-conformist (haven't gone into what) as well as the St Dunstan baptisms?
LONDON: Dr Williams' Library; Index to Register of Certificates: 8001-17116
James Plumb born 20 Oct 1831 Bpt 25 Dec 1831
Independent David of No 5 Sto?er Street Commercial Road St Dunstan Stepney
& Maria Susannah, dau of Thomas Andrews of Fitzroy Square
James Stratton Plumb Born 20 Oct 1831
Dissenters David & Maria Susannah
Robert Ayleworth Plumb Born 1 Sep 1835 Dissenters David & Maria Susannah
Thomas Emanuel Plumb Born 23 Mar 1833 Dissenters David & Maria Susannah
William Andrews Plumb Born 4 Jan 1837 Dissenters David & Maria Susannah