Hi Paul,
Sorry, but following the advice of Discourse Devs, i commented out Angus’s discourse-events plugin, but i also commented out Robert’s discourse-locations (since i didn’t find use for the location functionality, there’s no University calendar to test with)
Therefore, i won’t be able to help you diagnose the issue easily, because the unofficial plugin(s) isn’t on my only VPS now.
I hope you understand, and if you do, i’m really hoping to collect more votes on bringing the import functionality into Discourse Calendar (and Event) or event plugin, Feature Topic below: