How to bulk delete old whispers

So this task works well, thank you… but the whispers are simply collapsed and still viewable by Admins and moderators when expanded.

This does tidy up topics, but I was hoping they could be completely removed in their entirety. I wondered if the whispers could all be moved to a new topic, and that then deleted or hidden from mods at least, but then I found this: Is there a way to remove all the deleted/hidden posts? And more recently: Why is it not possible to permanently delete topics or posts?

Unfortunately the above suggest there is no way to permanently remove the data :frowning: