fold down both sides of the rear seat & you'll see the plastic part either side the parcel shelf locates into. You've got to remove both of these - 4 or 5 screws if I remember right. They are a little bit akward to shift as the seatbelts run thru them, but just gently pull them aside and they'll come free ok. You've got to take these off first as the speaker cup comes out up the way.
You can then see the two metal mounting points the speaker cups are attached to. If you look underneath them, you'll see the cups come out with just a 1/4 turn - left or right I can't remember which - and then the speaker is held into them with 4 screws.
Just too add to GS's post. When you have removed the torx screws that are holding the plastic 'speaker covers' in place you will notice that they will not then just 'come off'. This is because they are also clipped into place on the window side. Be careful when you try to unclip them as I bust the clips on my previous Lag doing this:crazy: