Hi Adam,
I wonder if something else is conflicting. What other plugins/themes are you running – could you share your system information (normally found in the Events → Help screen)?
Would it also be possible whether on your live site or – preferably – a test site to run through our standard troubleshooting steps and see if everything works as expected when only The Events Calendar, Events Calendar PRO and a default theme are running?
If there is a conflict and we can identify it, that might help us to work toward a solution here 🙂
Let me know how you get on!