So, I renamed .config/monitors.xml and this has sort of fixed it. I'll attach my old monitors.xml in case that helps anyone.
** Attachment added: "monitors file from $HOME/.config/monitors.xml" https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1011086/+attachment/3183069/+files/monitors.xml.old -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1011086 Title: X freezes after connecting external monitor To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1011086/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp