I found out what was causing it in the end, there were a few instances of "$stylevar[tablewidth]" being nested and the result was the side bar was being squashed and the whole window was being stretched as the variable was inserting a value of 955 each time. I've since changed all occurrences to 100% instead as I use a liquid style and now the templates stretch nicely with the screensize.
I would just like to say thanks for this hack, its just what I've been looking for (for ages) and when I can add thumbnail images to go with the files it will be perfect