OK, Blu-ray and Sky HD to Sony receiver via HDMI, plus an optical digital cable from Sky HD to Sony receiver. HDMI from receiver's monitor out to the TV.
Extra optical digital from the TV to an input on the Sony if you're going to be using the TV's internal Freeview tuner and you want to listen to that sound through the system - ie without using the Sky+HD box.
Speaker leads from the Bose input cable bundle to the appropriate speaker output on the receiver - front left, centre, front right, left surround back surround - plus the LFE phono plug in that wire bundle to the Sony's subwoofer output.
Other end of this connector into the Acoustimass module, relevant speaker cables out to the appropriate Cube speakers.
Done.