CaroleW,
That's great and curious too!
From 1881 Census Joseph and Emma had children: William (28), Mary (27), Joseph (25), Nathaniel (21), Emma, Richard, Frank and Arthur.
20 yrs earlier the 1861 census gives Joseph and Emma with children William, Ann (7), John (5), Nathaniel (3). This gives a discrepancy in ages (eg. Nathaniel either 21 or 20+3=23) and two children Ann and John who conflict with Mary and Joseph but their ages are spot on!
Would you have a child Ann and in 20yrs time call her Mary instead?
Regards...
Lindoo
PS. I'll start a new string, this one is getting a bit long.