Hi,
Have you seen the whole family in the 1881 census at Familysearch?
Alfred, 40
Sarah, 38
John, 16
George, 14
Alfred, 12
Fanny, 9
Emma, 6
James, 3
Mary J., 10m
All born Chepstow Monmouth and living at 1 Horse Lane.
This should give a few more clues.
ROs