The reason i ask about her remarrying is because all i can come up with for William Clansey is the following but the ages shown are out, its all i can find for a William though.
1841
Burnford Street, West Bromwich, Staffs
lodging with a Warwick family
William Clancey - looks like aged 10 though - born in county = y
and 2 doors down
Sarah Hayes - 35 - y
Sarah Hayes - 15 - y
Matilda Hayes - 10 - y
John Hayes - 8 - y
Thomas Hayes - 6 - y
Benjamin Hayes - 4 - y
George Hayes - 4mths - y
1851
More? Street, West Brom
Sarah Hayes - head - wid - 45 - West Brom
William Clansey - son - 23 - Moulder in Iron - West Brom
Matilda Hayes - dau - 19 - Charwoman - west brom
John Hayes - son - 16 - Moulder in iron - west brom
Thomas Hayes - son - 14 - moulder in iron - west brom
Benjamin Hayes - son - 12 - moulder in iron - west brom
George Hayes - son - 10 - worker in iron foundry - west brom
Sarah Hayes - gddau - 1 - west brom
1861
14 Smith Street, West Brom
William Clancy - lodger - 40 - Caster? - West Brom
I suppose these are quite random entries and ages would have to be out on each census, Sarah would have remarried soon after she married in 1821 to John Clansey and would have been widowed again!
can't find John or John senior at all