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