Thanks, turning on the “Minified” option has now resolved the layout. And the plugin is live on http://www.4g.co.uk/lg-g3-4g-phone/
However, it's obviously much better if we could resolve the issue to get the “timthumbs” working because i presume they reduce pageload times. And removing the error message so the plugin works as recommended can't be a bad thing.
What permissions should the folders have? I could get my server hosting company just to double check the permissions.
We'd rather wait and see if you can spot the problem before creating temporary logins and word-press accounts.