Howdy Linda,
Thanks for sharing the link to a problem event. I see your event there does not seem to be a complete address. Basically because that map is powered by Google from time to time it is quite possible that they will change their guess as to where a location is. This is just the nature of Google Maps unfortunately.
However you can usually help Google out by providing more complete addresses. In this case it looks like you are just providing Google a general area that probably doesn’t have any official boundaries. Could you perhaps provide a street within there? For example when searching this area in Google Maps it suggested the following address:
The Quay, Poole BH15 1HJ, UK
Could you use that instead, which will point to the middle of The Quay Street? Is the marker within that Google Maps link more where you expeced? If so you might try an address similar to the one it suggestsand see if it moves the marker where you want.
Does that all make sense? Will that work for you? Please let me know.
Cheers!
– Brook