Once again this morning, for the second time in four weeks, we have had a couple of hours of offline time. This is purely attributable to the hosting provider, and if it keeps recurring we will switch hosts. Both times they have blamed their "Litespeed" service, which I read is an alternative to Apache. Not sure what is going on but we'll just have to move if this keeps happening. Sorry for any inconvenience.
I don't think anything was lost, because I presume when the error happened and the system crashed, everything went down, so there was no need for a restore. If anyone observes otherwise please let me know.