Hi @graemeblake,
I not completely sure I understand what you mean. You can always see what the real title/description is the plugin adds by looking at the html source of any page(/post) on your website. Is there a difference between what's displayed in the snippet and what's in the source code of a page ?
Anyways, I've added your comment to the GitHub issue. Let's hope someone will be able to figure out what's going on.