Thank you for your thoughts. Firstly, as to the backups - I have looked at the old backup rotation script that I had written back in 2012 to deal with backing up saved games. This used the Linux "cp" command. I have now modified the script to replace the "cp" command with the "mv" command for all but the first backup (as it is important that the first backup is indeed a copy, as the original file needs to remain untouched). However, this would not address the issue described here, as the only corrupt backup was the first, which was (correctly) a copy of the current server save file.
I have looked over the logs and cannot find anything of significance: what appears to have happened on the 31st is that the saved game became corrupted at some point (I do not have the exact time as many of the logs were not timed - I have now modified this) and there came a point when the game could not be restarted. If Dr. Supergood's save was an automatic rather than a manual save from his end, I am not clear on why this failed on the server other possibly than that this was relating to cache settings, which I am not entirely sure how to adjust (a brief search has not yielded clear results - do either of you know how to adjust these?).
I have now restarted the server with the restored saved game provided by Dr. Supergood; I have also taken the opportunity to increase the maximum commuting time tolerance to 3 hours and also increase the maximum visiting time tolerance to 6,015 minutes and the minimum visiting time tolerance to 12 minutes (up from 8) to reflact changes made to the pakset since the server game was originally created.
I do note, however, that Dr. Supergood's saved game also does not appear to have password data retained. I have backed up the saved game that was in use on the server until this restoration in case of difficulty.