Hannah Barber married in Melbourne in August 1853. (On her marriage, she names her parents as Francis and Susan Barber)
She had possibly emigrated before the 1851 census in England .
I cannot see her in the 1841 census. She was possibly employed as a servant somewhere.
Her illegitimate son Favell Charles Forth was baptised 25 Sep. 1842 in Marden Herefordshire.
In 1841, Hannah may have been living somewhere close to her son's father.
EDIT TO ADD -
In 1841 Charles Wordsworth 35, barrister is living in Princess Street, Lambeth, Surrey
He is with his wife Elizabeth, daughter Fanny and a servant Ann Towsey.
Anna Barber (Hannah) baptised 10 Sept 1815, Withington, Hereford, England
Parents Francis and Susan Barber
Susan GARNOULDS married Francis BARBER
19 May 1814 Withington, Hereford, England