Ok, got it all fixed, had to edit via the database and so far it doesnt seem to have broken anything which is good!
(If anyone is wondering how I even managed this to begin with, its because I accidentally used a space between User and Talk which was fairly stupid of me. Should have made a back up before doing changes like this... live and learn though).
Some caveats are you still have the template at the top, but I guess thats easier to fix than rewriting the content in the destroyed namespace.
First up, get the namespace ID for the namespace you want to revert back. In my case it was "2"
SELECT * FROM `page` WHERE `page_namespace`=2 AND `page_content_model`="flow"
Double check you have the right rows before proceeding, dont want to make an issue even worse.
Then run the query:
DELETE FROM `page` WHERE `page_namespace`=2 AND `page_content_model`="flow"
Now to convert the archived pages back to what they should be:
SELECT * FROM `page` WHERE `page_title` LIKE "%/Archive_1" AND `page_namespace`=2
Double check again with the above select that you have the right rows.
UPDATE `page` SET `page_title`= TRIM(TRAILING "/Archive_1" FROM page_title) WHERE `page_title` LIKE "%/Archive_1" AND `page_namespace`=2
Once sure, run:
UPDATE `page` SET `page_title`= TRIM(TRAILING "/Archive_1" FROM page_title) WHERE `page_title` LIKE "%/Archive_1" AND `page_namespace`=2