I think you need the 1837 marriage to start with:
Dec 1837 Tonbridge 5 609
Harriet Giles to possibly George Clifton
It should show their father's names and occupations.
If my guess is correct as to her remarriage to Mr Groombridge, then later censuses show her birth place as either Robertsbridge or Salehurst ca. 1815. The pilot familysearch site (
http://pilot.familysearch.org/recordsearch) has a matching christening:
16 April 1815 Salehurst, Sussex
Harriet Gyles, parents Thomas Gyles and Lydia
but it's suggested that she was already age 5 at her christening.