I remember you suggesting that one before. I ordered it and it had one end that would attach to the car but the other end was the same as the car
. It couldn't attatch to the headunit's ISO ends
. Unless I seriously missed something 
I have used this one before to install a standard single DIN ISO headunit (like your Sony) into a MK5 Golf.
It should look similar to this one: -

So it takes the Quad Lock connector from the standard loom and then provides the the two ISO blocks, one for power and one for the speaker connections.