John Dansey, born c 1811. Nicholas/Lydia were thought to be his parents, but their children are well documented in St. Andrews and elsewhere. I am aware of Robert Dansey in the 1831 census, but that is slightly mysterious to track down as well.
John is mentioned (as coming from Wormingford) in a couple of ploughing contests in the area, and in 1841 is in Hutton, then moves to Navestock, then Wanstead.
We just can't place him into Nicholas/Lydia's family, and the dna test suggested that the progenitor was earlier.
Thanks - Terry
p.s. all of Nicholas/Lydia's children stayed locally, John "migrated".