Hi Marie,
It is many years later than your posting regarding William Quinnell and his parents, George and Hannah. I am sort of related

as Hannah married an ancestor of mine, after George died. She was then Hannah Watkins. I just wonder if you got further with your search?
I won't go into details here - just glad to have found William and his descendants. Hannah is hard to research (I am still looking for her birth-place and date) - all I know is that she was Hannah Charles and married George Quinnel in Bristol in 1815. George was Broker and Hannah's father, Robert Charles, was a Veterinarian. They lived in Swansea, where George died in September, 1841,and their daughter Eliza died in January 1842, Hannah married Thomas Watkins, a widower, in December 1841. Thomas was my Great-great-great-Grandfather.
Regards, Janice