Elizabeth was baptised in the same place in Sussex that Henry was born, in Litlington, which is very close to Seaford, as both are on the East Sussex coast.
What proof do you have that the marriage in Tonbridge Kent in 1823 was this couple (other than a marriage has been found on the IGI a very incomplete index of some parish registers) for a couple with the same name? Does John French's death certificate give his mother's maiden name?
The spelling of Mary's birth place on the 1861 census looks to be Coatham, so it isn't a spelling error for Chatham, though I wouldn't know in 1861 how a broad Kent accent would sound to a Sussex census enumerator (presuming Mary was the one to give him the information). I would have thought it could just as easily be a mistake for Cobham Kent, or some small Kent Hamlet I've not heard of. The only Coatham I know of is in Yorkshire.
FreeBMD is an incomplete index of the civil registration but it would appear that Mary died in Seaford (Eastbourne registration district) not Dartford registration district in Kent.
It might be useful if you ask for a look up on the 1851 census in Seaford for this Henry and Mary to see if they were there 10 years earlier and what Mary's place of birth was on that census, if she can be found.
The 1861 census shows one other French born in Litlington Sussex, Samuel born circa 1819. He is a farmer in Arlington Sussex in 1861.
The 1871 census shows even more French males born Litlington. Besides Samuel in Arlington, there is Charles born circa 1828 an ag lab who is in East Dean Sussex and James born circa 1822 who is a coachman in Alfriston Sussex.
According to the IGI the parents of these men were Samuel and Harriet French, as well as the parents of Robert French baptised in 1825, Robert and Maria. So a whole colony of French families, it would seem brothers (from the IGI) were in Litlington.
Regards
Valda
