Good evening Andy and welcome back!
Thank you for reaching out to us.
I would love to help you with this topic.
Actually, for the time being, this is the correct behaviour.
Having one set of the tickets for the complete series is the only option that will work unfortunately.
The reason for this is that we do not yet fully support recurring events with Event Tickets Plus.
You can read about that here: https://theeventscalendar.com/product/wordpress-event-tickets-plus/
The good news is that we are working on that feature.
However, I cannot provide you with a release date at this point.
In the meantime, the only workaround is to create the series and then break the individual events from the series. Once that is done, you will be able to create separate tickets in each event.
I realize this is not a great workaround, but for now, it is the only one there is.
Best regards,
Geoff B.