WikiTreer Debra Downs let me know about this webpage: http://www.familyhistoryalive.com/Naming-Conventions.html This is an excellent article about naming conventions in the UK. In short,
A similar pattern applied for female children. That is:
So given this arrangement, I should be looking for a father of my Earliest Known Ancestor with the name William. HHmmm. Back to the books. . .