I can't find her anywhere between 1851 and 1891...using Frederica with no surname, and correct date and place of birth found her in 1891
No matches on Familysearch of Freebmd for a marriage...
Tried surname Farrent/Ferrant date and place of birth with no Christian name and this was the only one and it doesn't match

NAME: John Farrant
SPOUSE: Jane Farrant
BIRTH: abt 1822 - Tidworth, Wiltshire, England
RESIDENCE: 1881 - Limehouse, London, England
I wonder if she emigrated then came back when she lost her husband?
Carol