How do I delete files in a chat?

We started a 'chat' and shared files in it. There are now a lot of files there but I can't find a way to delete any?

This is a limitation of the Microsoft software and will be raised through the Programme Board. In the meantime, it is possible to delete files in Chat by going to the original post and deleting it using the 3 dots option. This should also remove it from the Files tab, though will need to be done by whoever originally posted the file.