The DB is back now. Either the shared server crashed, or was being patched and rebooted or there was an internal network issue. I had a quick sniff at work and could see the hosting infrastructure was running and responding quickly but our stuff was unreachable. I got an error email from the SMS server saying there was “an issue” at 14:55 UTC and I looked at 16:00UTC when I got home and it was up and running. My money is on a patch and reboot.