Its held in by the screw in the ashtray, 2 at the rear (one each side by the seats) and 2 at the front on the centre console/dash (need to remove gear stick surround). You can get it off without removing the handbrake, but its a PITA.
You know, the bottom of the armrest cubby is just stuck down with tape - certainy was in my MY03 car. If you remove everything from in there, if you have the phone cradle, you can remove that and then just yank the "floor" of it off and it will get you access to where the BT module is. Not got loads of space, but if you are just wanting access to run cables etc, it gives you enough room.