Apologies for the server downtime today.
Basically I updated the server from Debian 7 to Debian 9 and this unfortunately broke a lot of things. For example the Knights server had to be recompiled and most of the PHP scripts on the site had to be hastily updated (because the PHP MySql interface has been completely changed, just to make things "interesting").
The reason to do the update was because Debian 7 is coming to the end of its support period so in order to get security updates, I had to move on to the latest version.
I had hoped the upgrade would go a bit more smoothly than it did, but never mind!
Hopefully we won't have to do this again for a while...