The little girl was born Glos as was Eliza. Maybe try tracing the name that way.
Could be Kate Potter King born Cheltenham Jun 1854. Maybe Eliza was a King and could find a marriage to Ralph?
I've just been looking at Kate I think her mother's surname may have been KING
KING Kate P
mmn KING 1854 Cheltenham she marries 1892
ANDREWS Matthew to
KING Kate Potter parish Charlton Kings district Cheltenham
1891 Kate King is with her mother Mary Ann King
also two gd/ children of Mary's Harry A (Augustus) & Robert A (Alexander) mmn King
There this marriage 1849 Stroud
MATHER Ralph to
KING Eliza info. from Gloucestershire BMD
http://ww3.gloucestershire.gov.uk/bmd/I think Eliza is the sister of Mary Ann King born c1829 Twyning Gloucestershire
Not sure it's the same Ralph from the 1861 census
Eliza & Ralph MATHER on the 1851 HO107; Piece: 2061; Folio: 609; Page: 20
living Dartmouth Street Warwickshire
Ralph 29 pob Glasgow occ Pin pointer
Eliza 27 Stroud Gloucester
Thomas 1 Stroud (mmn King see Gloucetershire BMD)
found her death
Eliza Mather age 45 (1822)
Burial Date: 22 Oct 1867 Burial Place: St Peter & St Paul Aston, Warwick
Spouse:
Ralph Mather