an update…
I am now able to login to the admin interface using my normal admin account I always used.
I found this topic
http://community.freepbx.org/t/invalid-username-or-password-after-user-man-update/37178
which mentions the admin account going missing so I looked at the database on my live server and compared some tables to my VM (which still works as it updated from before the mentioned troubled framework version to the fixed one) and found the ampusers table on my live was missing the admin account.
I manually added the admin account back into the database using the values (the hashed password mainly) from my VM as it was a copy of my live and now I can login again.
I do still, however, have the issue with fwconsole unlock not working so if anyone has any ideas I’d be keen to know to try get this working for the future as it certainly could be useful.