I am not comfortable linking my UniFi Controller to MyPlace as we have lots of clients there?

Good point, and indeed we suggest that you don’t do this if possible. Ideally you should create a new admin for the site that you want to connect, and then use those credentials to connect with the MyPlace service. If you ever need to add another site from the same controller you can simply extend the priveleges of the new admin user. Even at that, the MyPlace service has very limited functionality within the controller and can really only change the guest portal function