27/03/25 – Postscript:

This maps gets cropped a lot and reposted online (to widespread distain). I am trying to right a wrong here; I should never have published the map. I filtered the data by historic=castle. This tag is far too broad and includes historic houses, I have updated the image to reflect the issue. I have decided to leave it up here so that when I see it posted in future, I can link to this post to explain the error.