I can't find the thread I was on about the issue. It's been nearly a week now of freezing.
It's the only site that's doing it.
Usually fine on the menus, but go onto a thread and the whole thing freezes. I have to wait a moment then change the address line to Google, which gets rid of MN but doesn't actually load Google, however I can then move away from the site and close what had been its page.