Trying to find and prove the demise of Elizabeth has been driving me crazy

there are many possibilities, the Elizabeth Rogers death in 1777 at Laugharne, Carmathenshire is a big coincidence.
I have narrowed down the possibilities in Norfolk down to 3 candidates illiminating: married to another mans name, infants, widows and burials whereby the age is not correct, unfortunately the place of burial each time is not encouraging:
i. buried 15-09-1764 Gissing
ii. buried 09-07-1766 Weasenham
iii. buried 06-09-1773 Frettenham
The list of Elizabeth Rogers' buried in London is just too long. The Elizabeth buried 21-07-1782 @ St. Brides suggested by Ili1133 is a nice possibility being 2 years before the second marriage of Joseph but there are other such burials listed in the London area.
@ Ili1133 Indeed a non conformist burial is also an option.
The facts give us Joseph and Elizabeth living in Norfolk born (and bred?) although I am still unsure as to Joseph being born London or Norfolk

For some reason they move to Wales (in 1777 their eldest child would be 17) with an Elizabeth Rogers being conveniently buried in 1777 (did they move to Wales for health reasons)
After 1777 Joseph goes dark until he pops up again in Londen for his second marriage. As Ili1133 mentions, the answer could lie in Josephs whereabouts in this period?
Oh well, ramble over, back to the drawing board
