Sorry for the few hours downtime. I had messed with some firewall configs, then rebooted the machine. The machine netboots by default (and then based on a setting decides whether to boot the disk or a recovery system). Unfortunately the tftp server had gone wrong so it sat there unable to boot until I got in contact with support, who then fixed it.
Unrelated, but http://www.exotica.org.uk and http://www.jogglerwiki.com are now available over IPv6.
Info on my hosting setup can be found at http://www.exotica.org.uk/wiki/ExoticA:Hosting