Thanks, it is possible that he had died before the 1841 census but I have not found a death but Jemima is recorded as widow in 1851.
I have found 3 deaths which are around the right time. 1838 is the one who died in London aged 38. Another one in 1848 in Truro an 82 yo Tide Bailer who could be the father of the one who died 1838 and another one in 1849 a 74 yo Husbandman in Phillack. I have not been able to prove any of them are the one I am looking for.
The 1838 Richard died in London and had a family there.
The 1848 Richard is probably the father of above Richard as Rev William Woon his son in NZ stated in his diary that his father died in 1848 in Truro.
The 1849 Richard has a daughter Ann who married the informant Pellow and was living in an area not associated with the family but not impossible.
I guess it is possible that he had 2 families but living in a different town would have made it difficult and both families had children born in the years 1836/7 in the different locations. The London family had children between 1825 and 1837 and the Cornwall family between 1835 and 1839.
I so far have no DNA match to Richard Woon 1800-1838 to Richard Woon and Jane Trestrail or any of their other children, but I do have matches further back.