Well I haven’t sorted the calander yet, but I do seem to have managed to retrieve all my missing entries. They really were missing – probably as a result of the corrupt database, but the old HTML tables still existed on my server, so I was able to reconstruct the entries and import them back into the database.
I must admit that it’s quite a slow and painful process, and not something I want to repeat. So regular export backups shall now be the order of the day. And that starts as soon as I complete this entry!