@adamsdesk The posts in question aren't strictly Mastodon posts, but part of a Wordpress blog that publishes via an Activity Pub plugin to Mastodon (and other platforms).
Because I've already deleted them on the blog, I can't repeat this - and I have no way of "logging in to Mastodon" as the post author to get them deleted any other way.
Whatever happens would have to happen either via Wordpress, or by some cache maintenance mechanism of the Mastodon instance, if such exists.