There is a death of Ann Northam in Mar 1/4 1841 Ref 10/256 in Chard (which I believe covers Yarcombe).
THere is only one Simon Northam on 1841 census . could this be their son:
NORTHAM, Simon 1793 Devon
NORTHAM, Mary 1794
NORTHAM, William 1818 Devon
NORTHAM, Ann 1828 Devon
NORTHAM, Henry 1831 Devon