Well it looks from the 1851 as though James Southgate 1846 MMN Carter is the son of Thomas Southgate from Hadleigh (transcribed Ardleigh but I'm sure it's Hadleigh) and Ruth born Nayland, Suffolk the same place as a wife Martha in later censuses - because a Thomas Southgate married a Ruth Carter (or any of 3 other women of course, but none called Ruth) the previous quarter same district.
I can't find a nearby marriage of a Thomas to a Martha, maybe Ruth started using a different name - but that's not relevant to this search. There's another Thomas Southgate found in Colchester born late the next year (seemingly to William Southgate and Elizabeth nee Woods) but he seems a bit young to be the one in later censuses, and the Thos Southgates consistently work on the railways.
What this means is that John Southgate born c1824 Kirby-le-Soken is uinlikely to be a brother of Thomas Southgate b c1829 either of the Hadleighs but I think this needs someone with more experience of this area to contribute - I've never researched Essex or East Anglia before.
