Remove the six screws from the door card...
2 x around the door handle (after removing cover)
1 x deep set in the door armrest
2 x at the door pocket corners
1 x right at the bottom centre
After removing the six screws the door is now being held in place by 15 or so plastic trim clips around the door card edges.
Grip the door card firmly at the far edges; pull the door gently towards you. Now jerk the door away from you sharply, the sudden jerky action should release most of the clips without causing too much damage.
The trip clip mounting pilars are prone to breaking away but you can easily glue these back in place.
You'll need to pick up a pair of speaker mounting adapters (Halfords) to fit your speakers in the orignal locations. You may also want to replace the stock door tweeters while you're at it.
