I checked Page width controller in Style Props and it's the same on both boards.
I reduced the width of the sidebar but it makes no difference. Something in the main content area is pushing the width unnecessarily. Or the header?
(my logo is the same as the other board so it's not that.)
Here it is http://fcuk.dev.waindigo.com/ (temp location)
(scuse us we're not fully dressed yet!)
EDIT - the admincp is also wider!