Hi Paul
I wonder , this could be her:
1891: Havant, HampshireRG12- Piece: 851/ Folio 52/ Page 3
Address: Lymbourne??
Head: Willena DAVIES 25, married, b Wandsworth Surrey
Dau: Gladys B E DAVIES 6, Scholar, b Wimbledon Surrey
Son: Laurence G DAVIES 5, b Wimbledon Surrey
Now, Wimbledon (3 miles from Wandsworth) I think, fell under the Kingston Reg district.
The probable birth for Laurence G is:
Laurence George DAVIES -
Wandsworth - Jun Qtr 1886
I find no birth reg for a Gladys DAVIES 1884-1886 in Kingston or Wandsworth, other than your Gladys Bertha H....

In Sep Qtr 1884 Kingston -
Marriage of a Willina ROSAM.
One of the possible grooms was: George DAVIES
1901: Hove SussexRG13/Piece: 935/ Folio: 50/ Page: 6
Address: 26 Brunswick Terrace
Head: John BAKER 732, wid, Knight Bachelor, b Portmouth Hants
Son: Reginald J E BAKER 27, unm, Living on own means, b Portmouth Hants
Dau: Hilda M BAKER 22, unm, Living on own means, b Portmouth Hants
Servant: George DAVIES 43, marr, Coachman Domestic, b Titley Hereford
Wife: Willina DAVIES 35, b Wandsworth London
Dau: Gladys B E DAVIES 16, unm, Apprentice to Milliner, b Wimbledon Surrey
Son: Lawrence G DAVIES 15, b Wimbledon SurreyPlus servants: Cook, Kitchenmaid, Footman, Parlourmaid and 2 Housemaids
The Reg District for Hove Sussex is : Steyning.
And Steyning is the Reg District which records the 1908 marriage of Gladys Bertha H DAVIES to Thomas REDMAN....
Food for thought anyway! Looks like the birth cert of your Gladys may be needed to clarify her parents.
Cheers
AMBLY