Working backwards
Thomas NEWINGTON of St Nicholas, Brighton was buried 18 Apr 1831 aged 65 thus a birth around 1766.
His wife Louisa Ann NEWINGTON nee NASH was buried near her husband Thomas on 07 Jul 1848 aged 70.
Thomas was a widower when he and Louisa married 24 Jul 1823 at St Giles, Camberwell, Surrey.
It seems Thomas previous wife may have been a Mrs Mary NEWINGTON also of St Nicholas, Brighton buried 3 Sep 1809 aged 43 thus a birth around 1766 [about the same age as Thomas].
There is a marriage between a Thomas NEWINGTON of Brighton [a widower] and Mary KENT [a widow] at Brighton 16 Jan 1805. Is this Mary the Mary KENT buried in 1809 as above?
A possible marriage for a Mary to a KENT is the marriage of Mary GRENVILLE & Richard KENT 12 Jul 1788 with a Richard KENT bur 5 Jan 1801.
However we need another marriage for Thomas as he was a widower when he and Mary KENT married.

All assistance welcomed.
Westy