Messaged Fandom Support and they were really cool about it, we should be able to download the data and move it to the new site!
"Fandom does not allow wikis on our network with explicit content, or about explicit topics. We have recently turned our attention to various wikis that fit these criteria but haven't been caught in our screening process. Unfortunately this means that we are no longer willing to host your wiki.
You can get a download of all articles from the links on the "closed wiki" page. Unfortunately we are not able to provide images or Discussion threads.
I'm sorry to give you such bad news, and hope you find a suitable home for your content."
So there is a hope that it's just a case of migrating the data!
Also big shout out to Fandom support for being respectful about it all.