Len, just in case you don't have this information:
William Hopkin's 2nd wife Mary Hanes, mother of George Hammond Hopkin born c1832, was a widow when she married William in 1831. I think she may have been born Mary Smithee and married John Hanes in 1817. It's possible that they had a daughter Mary Smythee Haynes who married William's son Abraham Hopkin (born c1815 Denver) in 1837. (If this is correct then they would have been step brother and sister). Mary (widow of William, he died in 1839) is shown on the 1841 census aged 44, living with Abraham and Mary Hopkin and family.
Link for marriage of Abraham & Mary Hopkin (nee Haynes/Hanes)
https://familysearch.org/pal:/MM9.3.1/TH-267-12652-6180-40?cc=1416598&wc=92B5-DPV:29473001,29373001,29586501if you look at the marriage cert you will see that Mary was a minor and her guardian was William Hopkin who was also a witness to the marriage
Marriage for John & Mary Hanes (nee Smithee)
Name: John Hanes
Spouse's Name: Mary Smithee
Event Date: 27 Oct 1817
Event Place: Emneth, Norfolk, England