How do I delete a retracted extension?

I have an extension that I uploaded a while ago, but have since retracted. I'm now ready to upload the new version, but I can because the package name is taken by the old version. If I navigate to the old version (by going to My Products, and ticking the "show retracted" box), and then click on the old version, this is all I see:

As you can see, there's no delete button along the top, like there is for a draft. Does this mean that extensions that have already been published can't be deleted? How can I completely delete this old version?

Thanks