Try to load all files (images, scripts, etc.) with a full path including even protocol and domain.
So instead of using this: /site/assets/files/1114/livery-corporate.png
Try this: http://www.justrightmarquees.co.uk/site/assets/files/1114/livery-corporate.png
Maybe this gets the job done: <base href="http://www.justrightmarquees.co.uk/" />