Still no reply from Gigabyte support it seems that 5.1 DDL in games just doesn't work.
Have now tried updated BIOS, reinstall of drivers, clean windows installation.
I downloaded the Dolby Live Control Panel from Intel and that works fine with all 5.1 speakers in the test yet games still only 2.1
Think i'm going to throw this piece of crap in the garbage and get a proper board with enough slots so I can put my very old PCI Audigy back in there as that worked a treat in 5.1 with DDL in all games.
This Gigabyte board is just utter s***e and the lack of responce from support just confirmed my suspicions that they know full well that 5.1 DDL doesn't work in games despite being advertised as a fully DDL board.