NSABaits:
sorry Clyde maybe i'm confusing matters with the issue I have.
if I change the width of the left column it does not expand the width of the categories box to 100%
This is the left hand column at 500px. As you can see the categories box is not 100% width.

The boxes are confined to a width of 150px.
As I mentioned earlier if you want to make them wider you have to adjust them here:
admin -> configuration -> layout settings
Column Width - Left Boxes 150px
Column Width - Right Boxes 150px
You will also then have to redo the images that make up the sideboxes to whatever width you choose.
The boxes are not dependent on the width of the columns.
You can change the column width all you like but unless you change the width of the boxes they will remain set at 150px.