Hi there Dan,
Thanks for getting in touch with us! I can help you here 🙂
The month view of our calendar has switched to using Monday as the first day of the week
Did you recall any recent changes that could affect this? Maybe installing a new plugin?
…the “First Day of Week” setting as described here is not present on the General tab
I find this quite strange as this is a default WordPress setting and not something our plugin is adding.
Can you please try updating The Events Calendar and Events Calendar PRO to latest versions? Once that’s done, re-check to see if the setting is back. In case it’s not, Can you please follow the steps described in our Testing for conflicts guide? This way we can see if this is a problem in our plugin or a conflict with the theme or other installed plugins.
Please let me know about it,
Best,
Nico