Where is Rebecca in 1851?

[Phoenix]

Rebecca Newman marries John Miller at St Giles Cripplegate in 1802:

https://www.ancestry.co.uk/interacti...nSearchResults


One of the witnesses is John Fray.


John (a bricklayer) and Rebecca have two children: Ann Jane and John Fray.


Here is Ann Jane's baptism on 31 Agust 1806:


https://www.ancestry.co.uk/interacti...nSearchResults



Something catastrophic happens and John disappears from the scene.


Here are the children, being discharged from the workhouse into the care of their mother on 21 August 1813:


https://www.ancestry.co.uk/interacti...=successSource


I'm not sure what happens to John Fray Miller, but Rebecca takes Ann Jane with her down to Portsmouth and marries William Polling 13 June 1814 in St Marys, Portsea:



https://search.findmypast.co.uk/reco...2F00028251%2F2



In 1841 she is living in Pye Row, Portsea, next door to her daughter, aged 50 and not born in county:



https://www.ancestry.co.uk/interacti...cklabel=Return


Rebecca dies 21 December 1859 and is buried on Christmas Eve, widow of Pye Street aged 82:



https://search.findmypast.co.uk/reco...ERY%2F00014630


So where is she in 1851? If not in Pye Street, where? She has a year of birth somewhere between 1777 and 1790 and she could, of course, be staying with son John or any other relation.