Thanks for your replies. I received a reply from Richard Vandersteen (cool) saying he couldn't be sure what the issue was. He also said they do not have replacement woofers (interesting) but I can send the defective one in to them to be repaired. Maybe the current woofers available are different specs? Probably.
I'm ok with a little bit of diy to get these things up and running again. But, I think I would prefer just popping in a replacement woofer if possible. Anyway, getting reqdy to open it up. Just watched a youtube vid on removing the sock. Wish me luck! 😅