The Google Maps API server rejected your request. This IP, site or mobile application is not authorized to use this API key. Request received from IP address 2a00:23c0:ea81:1a01:d5d:2352:50bd:b7ca, with referer: http://www.penninelancashirecommunityfarm.org/opportunities-for-volunteers-a-year-review/
You have inserted wrong referrer in the google console that's why you are facing this issue please insert this referrer *penninelancashirecommunityfarm.org/* on google console and your issue will be resolved. I checked your maps with my API key and your map is working with that.
Please insert correct referrer on google console.
I have created a new location "Mumbai" for testing and location is created without any issue and your api issue is also resolved. You can check created location at manage locations.
You are most welcome, I hope everything is sorted out at your end.