[bug] atom feed changes result in duplicated posts

[Godley]

I fixed a problem in my atom.xml for my blog, and that meant the url changed from the (wrong) https://blog.charlottegodley.co.uk/<blogtitle> to just https://charlottegodley.co.uk/<blogtitle>. This seems to have resulted in my blog posts showing up twice, one which has the right url (first), the other which leads to a dead link (second):

It would be good to have a way to flush your own cached blogs in this situation, or else have an admin button for people higher up to be able to select a user and purge their cache if you can't trust users to self service :)