Cored hulls scare the bejeebers out of me.
Here is a
link to a David Pascoe article on cored hulls.
One of my favorite sailboats of all time is the Nonsuch 30. It does, however, have a cored hull and thus I would likely not buy one, even if it passed a survey.
Is there a Beneteau Owners Forum that is independent of the factory? If so, it might be work asking the question of that group of owners.
Jim