im pretty sure my system only has one sub cone in the back situated in the middle of the parcel shelf. With a black sorta mesh over it. Not a speaker i dont think. I will have a look but will it be one of the setups above definatley?

 

Definatley one sub cone in the parcel shelf... and a section looking underneath the parcel shelf that seems to be where the amp might be. So look like neither of the two diagrams above

 

Please note that this is the new shape A4 if that makes any differance, which im sure it will.