The antivirus error was because it couldn't get a lock on the db. I removed the directory, recreated, set it to be owned by zimbra and it appears able to start.
Not sure that mails are going through properly yet, as it seemed to hold one I sent to another user at our domain. Rebooting to check it's ok. Issues of stats claiming not to be started and not able to see mail queues remain. The same error with java numberformat exceptions comes up each attempt.