Mary Ann Nodes is difficult to find on the census. However I think she married Alfred Nodes in 1867 (Free BMD) and then as a widow she married John Sumner Barton, a widower 28 September 1878 St John Hackey. She named her father as Henry Oliver Nodes undertaker, so its definitely her.
Alfred Nodes appears as a baby on the 1841 census as the son of George Nodes undertaker. George (Alfred) Nodes married Maria Barton 5 May 1840 St Pancras. I guess that's what they call keeping it in the family!
Carole