There are currently some performance issues on the VM hosting the server.
From my initial investigations it looks like it may be due to a "noisy neighbour" on the same VM host node.
I'm in contact with Bytemark to try and resolve the issue.
This might be a good time to take a short break from the forum...
Update: I have put the forum into read-only mode so it can at least be browsed.
Update 2: I've made some tweaks to Discourse to reduce its resource requirements. It should now work but will also be much slower.
Update 3: Bytemark were doing some maintenance to their infrastructure so some VMs were impacted by reduced capacity. Everything is back to normal now.