Although you mention two surviving children, one tree has another
Sarah Ann Standen, daughter of Charles and Susan, baptised in Gamlingay on 1st October 1837.
She married William Endersby on 11th November 1855 and is on the 1881 census at Cottage, Everton, Biggleswade, Bedfordshire, with five children.
Living with he son, Charles, in Gamlingay in 1891 and 1901, and died there in 10th February 1904.