Pete,
The description from your article should be set using the Open Graph features of JFBConnect. Open Graph is how you describe your site to Facebook when used in wall posts and sets things like the title, description and image.
By enabling the Open Graph - Content plugin, that should automatically set 'good' tags for your content, but you can override those as well if necessary (I can explain more if you'd like).
Once you enable that plugin, you can use the
Facebook URL debug tool
to test what Facebook 'sees' on your page as well and could give you an idea of where things may be wrong.
I hope that helps, but if not, let me know.
Thanks,
Alex