I think this Sarah is Sarah Mann (line 2):
https://www.ancestry.co.uk/interacti...&usePUBJs=true
and this is her second marriage (goodness knows if the man is the same person!!):
https://www.ancestry.co.uk/interacti...nSearchResults
Here's the 'other' William who also says he's the son of Josiah:
https://www.ancestry.co.uk/interacti...nSearchResults
No sign of any of them after 1851!