Ah, going by Anglo-Saxon law if it can not be passed by birthright the Witan gets to decide.. it was the Witan who confirmed the crown passing to Harold Godwinson.

But even Harolds claim to the throne was not as strong as Edgar the Aetheling who as the last member of the House of Cedric and the rightful heir to the English throne, but, here is the kicker, was only 10 years old at the time, and William took him hostage..