Picade 10" Screen Black Borders

Hi All,
I have successfully built and got all aspects of my picade functioning and enjoying the experience greatly.
However one thing that is annoying me is the black border (unused pixels) around the screen (about 0.5cm all around).
I have tried the suggested fixes of removing the #comment from the config file to disable overscan. I have manually reduced the #overscan values to zero all with no effect.
Also the HMDI #safe setting is not uncommented so it is not defaulting to a preset.
I have run out of ideas to fix this. Does anyone have any ideas as to how to fix please?