There is a tree on Anc. which has the parents of Elizabeth Finn (who marries James Roberts) as:
Father: William Finn Born 1799 Lenham, Kent. Died 1868 Hollingbourne, Kent, England (no parents)
Mother: Mary Fuller Born 17 Aug 1806 Egerton, Kent, England died 7 Dec 1891 Kent (no parents)
There is no indication on the tree of how they have linked the parents to Elizabeth Finn.
However I have found a 2nd tree which shows Elizabeth Finn (daughter of William Finn & Mary Fuller) marrying a James Earle. Again this tree does not have a source link of Elizabeth to the parents.
There are a variety of other trees which have various information but none sourced.
Ray