Well I've figured most of it out in the meantime,
I just had to add this to my ~/.asoundrc config file:
pcm.!default {
type route
slave.pcm surround51
slave.channels 6
ttable.0.0 1
ttable.1.1 1
ttable.0.2 1
ttable.1.3 1
ttable.0.4 0.5
ttable.1.4 0.5
ttable.0.5 0.5
ttable.1.5 0.5
}
I now get stereo sound playing on all the outputs.
The only problem I have left is that volume control only adjusts the volume on the front left & right speakers
Anyone have any ideas/suggestions how to fix this?
Thanks