I have a John Tumber in my tree born c1813 in Wingham, Kent who worked as a farm bailiff. He was married (hard to read on census could be Esther or Eother) and had 4 children, George 1838, Sarah 1940, Ann 1843 and James 1846 all born in Wingham. George worked as a farm boy. I have seen them all in the 1851 census but none of them are anywhere to be seen in the '61 census. Also I can't find any entry for marriage for any of them. I wonder if this could be your John?