Related Posts – Categories Missing

Hi,
After the last two ‘related posts’ threads I posted, I went and delved a little deeper into this issue.
On activating Design-Single and then activating one by one first the Categories, and then the Tags, it appeared that the Categories were not appearing – or at least not appearing in the list of categories and tags under the featured image of the posts – only the tags were appearing.
Is this the reason that related posts wont show category related posts?

The page I need help with: [log in to see the link]