Chris,
Thanks for the before picture and live site. I'm not seeing any real errors on the site that would be preventing the slideshow from working. The only Javascript errors present are:
Uncaught TypeError: Cannot read property 'addBeforeDeferRunFunctions' of undefined www.urbanrec.co.uk/:74
I believe this is coming from PageSpeed, but not sure
Uncaught ReferenceError: jQuery is not defined k2.js
That's definitely coming from K2
The first one is interesting because we haven't done a lot of testing with PageSpeed. I can't imagine their screwing up our code too much though, but it's worth trying to disable to see if that fixes the problem.
The K2 one is because JQuery doesn't look to be loaded on your page at all. That's required by JFBConnect as well, and you can see that if you click the Login with Facebook button, it doesn't work. It's also possible that your slideshow feature needs jQuery and, without it, the page is choking.
You should enable the jQuery inclusion in JFBConnect, K2, or anywhere else to make sure it's properly loaded on the page.
I hope that helps get you started,
Alex