That worked! We are definitely getting there. But what I am really trying to do is show either the Tag or the Description, but not both together.
The reason for this is that the template only puts the Description on the archive page, not the Tag. So if I want the Tag as the title in h1 on the archive page, I have to put it in as part of the Description. And if I do that at the moment, I then get two copies if the title.