Hi media monger,
I've logged into your site, and I've set up my own test site and installed K2. It works fine for me, and I used the same settings you have on your site. So everything is set up properly. You can tun off front end editing in the K2 configuration, but I see that you have it on.
There are obviously three potential sources for the problem since the set up is correct, Joomla, K2 or the template.
Can you try switching the template and see if it shows in a default template? You're template may not be fully K2 ready. That would tell us if you should contact the template company.
You can also try reinstalling k2, in case something happened with the K2 install. If you haven't done any modifications to Joomla, you can also use Akeeba Admin tools to reinstall Joomla.
Right now I don't see any reason why it shouldn't be working.