Slowly Closing In...

So after finding the marriage certificate for John Curtis and Sarah Wells, which revealed he was from Tydd St Giles in Cambridge, I have found this couple on the 1841 and 1851 censuses living in Tydd.
The 1851 census states that he was born in Walpole St Peter (Wisbeach), Norfolk.
The Latter Day Saints IGI gives us the parish records for all the Curtis names in Walpole St Peter, and from those we can deduce that there were three families there giving birth to children around 1790s.
There are:
Luke Curtis and Mary
Thomas Curtis and Mary
William Curtis and Agnes

Here are the entries, but we will notice there is only one JOHN Curtis!

William Curtis England, Births and Christenings, 1538-1975	christening: 27 Feb 1795 Parish Church of Wisbeach-St. Peter, Wisbeach, Cambridge, England residence: Wisbeach, Cambridge, England	parents:Luke Curtis, Mary
Mary Curtis England, Births and Christenings, 1538-1975	christening: 16 Aug 1795 Parish Church of Wisbeach-St. Peter, Wisbeach, Cambridge, England residence: Wisbeach, Cambridge, England	parents:Tho'S Curtis, Mary
William Curtis England, Births and Christenings, 1538-1975	christening: 26 Jun 1796 Parish Church of Wisbeach-St Peter, Wisbeach, Cambridge, England	parents:Luke Curtis, Mary
Elizabeth Curtis England, Births and Christenings, 1538-1975	christening: 02 Jul 1798 Parish Church of Wisbeach-St. Peter, Wisbeach, Cambridge, England residence: Wisbeach, Cambridge, England	parents:Thomas Curtis, Mary
John Curtis England, Births and Christenings, 1538-1975	christening: 30 Aug 1798 Parish Church of Wisbeach-St Peter, Wisbeach, Cambridge, England	parents:Luke Curtis, Mary
Elizabeth Curtis England, Births and Christenings, 1538-1975	christening: 02 Jul 1798 Parish Church of Wisbeach-St Peter, Wisbeach, Cambridge, England	parents:Thomas Curtis, Mary
Joseph Curtis England, Births and Christenings, 1538-1975	christening: 06 Sep 1791 Parish Church of Wisbeach-St Peter, Wisbeach, Cambridge, England	parents:Thomas Curtis, Mary
Aza Curtis England, Births and Christenings, 1538-1975	christening: 21 Apr 1790 Parish Church of Wisbeach-St Peter, Wisbeach, Cambridge, England	parents:William Curtis, Agnes