The side was down for 15mins ish at 0100 GMT
I ran the update script which should be totally safe. Updating localsettings failed as there were localchanges. I stashed the changes, and re ran it, forcing the github copy of localsettings onto the server. This broke the site.
Someone made changes to the copy of two localsettings files on the server. Please can I emphasize that you should never do this. All changes should be made in git, and then pulled to the server (/update.sh).
btw, was someone also noticing who rebooted the server midway through me fixing it? Where do we discuss things in real time these days?