Joan, Thank you for the information on Mary's death.
I had the information about their marriage because of a research project in the Channel Islands, not because of a genealogy interest, so learning what happened to Mary after she disappeared from the Channel Island records closes the book on her for me.
Re: the pronounciation of Hamon - although I'm not sure what a Lanchashire accent sounds like, I've seen Hamon transcribed as Hammond before when written by English speaking people, such as census takers, but the name is definitely spelled Hamon in the Channel Islands and has been at least back to the 1500s. I think of it as being pronounced as Hah-moan rather than Ham-an, but it's been a while since I've been in the Channel Islands so I can't swear to its pronounciation.