Charlotte died in infancy - her death is on FreeBMD
http://www.freebmd.org.uk/cgi/search.pl, Thrapstone reg. district, Dec Q 1844. The IGI has her christening in Islip, Northants on 7 Apr 1844, and also 3 of her sisters: Louisa (1 Feb 1846), Rebecca (18 Mar 1849) and Hester (12 Jul 1857).
I looked for her sisters on the censuses, and found the family in 1851:
HO107/1745/159/18 - IslipGeorge Briggs Head 45 Ag Lab b. Unknown
Sarah " Wife 37 b. Thrapton, N/hants
Ann " Dau 10 b. Islip
Luezer " Dau 6 b. Islip
Rebecca " Dau 3 b. Islip
(That has to be the best spelling of Louisa I've ever come across!)
Will look for other years.
Rambler