Hi kentfarst
I’ve updated the API key with the one you’ve provided, and the media page is back up and running, which gives me some peace of mind to know that the issue is now on the Google API side of things (as you’ve indicated).
I have then set it back to my api key and cleared out the referrers (as you’ve suggested) and the media page is working.
I adjusted my Referrers to the EXACT pretty URL where I’m using the WP Theatre plugin and its working now.
Thank you very much for your assistance.