You could well be right Owen, I was not aware of the James Miles - Hannah Thomas marriage. Was there any mention of fathers' names? I was only able to obtain John's marriage because his wife had such an unusual name, obscure biblical character the daughter of Caleb.
Goodness knows where the Miles and David families originated. I have some Miles in my tree going back to the 18th century in Kington St Michael, Wiltshire.
Dave