Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
@ss3000
Try setting the overscan in /boot/config.txt using:
Edit: Of course if that works, you may have to reconfigure your RetroArch display settings to accomodate.
Ok guys, I have just redone the SD card and it's working perfect - as far as I can see the config file is identical to what I had it as. I have no idea what happened there but to be honest, its now working and the kids are happy so all is well.
Thank you all for your help and suggestions.