A very interesting question that is difficult to give a finite answer, because of spelling variations.
However, a Thirza Anstee was a servant in Bitton in 1871.
A Thirza Anstee married an Austin Hall in 1872, Holy Trinity, Bristol. her father's name William Anstee. (
https://familysearch.org/ark:/61903/1:1:NF56-XGV)
A Thirza & Austin Hall can be found living in Bitton, Gloucestershire in 1881, with their family (misspelt as Hale).
Austin Bush Hale 27 (born Bitton)
Thirza Hale 28 (born Doynton)
Kate Hale 9
Emily Hale 7
William Robert Hale 4
An Austin Hall age 30, died 1884. (Keynsham 5c/467 q March 1884).
There is no birth registered in Gloucestershire 1850-1855 of a Thirza A****.
There is a family tree that may be helpful which has Thirza as the daughter of a William Anstee (1816 Doynton) & Harriet Reynolds (1818 Doynton). They appear in Census, as Ansty, Anstie, Anstee, but the 1861 Census, has Thirza listed as Thirza Anstee.
https://familysearch.org/ark:/61903/1:1:M7KL-JBH