Now a bit worried that it might not be the mobo thats the problem, especially as no recovery via dual bios. Would be one hell of a coincidence if it wasn't the flash thats causing the problems though.
Queried Gigabyte and they say..
"If the problem still persists, the BIOS chip might be corrupted/defective due to unsuccessful flash; please contact your vendor for checking out the M/B or the replacement, if under their warranty. "
and
"This does happen on occasions when updating BIOS as the whole BIOS updating procedure should be treated with extreme caution. If you do not encounter any system instability or bugs with the current BIOS version, we suggest that you keep it. However if you are determine to flash BIOS, you are taking a personal risk of BIOS flash failure."