Hello Nigel,
Thanks for going Pro and welcome to the forums!
We are aware of this bug and our team is working on a fix. Until the fix arrives there are 2 things you can do:
Either 1) go to your database, wp_options table, and from there delete the option with the option_name tribe_settings_sent_data.
Or 2) You can downgrade to The Events Calendar 4.1.3. That version is free of that bug.
I am going to close this ticket to new replies, but the issue is still open and we will update this ticket once we release a fix.
If you have any new questions or issues please create a new ticket and reference this one.
Thanks and cheers,
Andras