Cheers Dave.
The unit has outputs for front, rear and sub woofer.
The wiring adaptor only has a white and red RCA for front speakers and yellow and red RCAs which I have plugged into the rears on the unit. There appears to be something coming from the sub, so I assume the Bose unit takes care of sending the signal?
The volume is not very good to be honest.
I need to look into the cost of a booster and how to fit.
There should be an RCA back there for the sub too