This issue often occurs when the screen ratio of the TV / Wall display screen is different to the monitor used when the dashboard was built.
One simple trick to address this issue is to use the dashboard sections to add a little false ‘padding’ to the side of the dashboard so that the ‘body’ of the dashboard is at the correct ratio for the display screen
The way i normally do this, is by testing the dashboard, by running it in full screen, with the same aspect ratio, and resolution as the wall mounted monitor.