You have two ways to remove the speakers, the first is to pry the grill BUT you WILL break it. I don't recommend doing this. The other is as follows
1/ Remove dashboard cover (if fitted)
2/ Drop fuse cover down (it is best to remove panel so it does not get damaged, remove by prying the black pin on the left hand side out by using a large flat blade screw driver and twisting the blade behind the black pin's head.)
3/ Undo 2x screws holding the trim onto the side of the dash nearest to the doors.
4/ Undo 1x screw at the lowest corner of this trim (hidden where the fuse cover was) and remove trim carefully.
5/ Using a torch locate 4x (sometimes only 3x) screws in the side of the side air vents where you have just removed the side trim. You will find two of them down small long holes, thus the torch. This trim should then just about fall out, do not force it because you may have missed a screw.
6/ Remove the glovebox in a similar manner to the fuse cover trim, the black pin is on the right hand side inside the glovebox.
7/ Follow steps 2 to 4 as per the drivers side but the lower screw for the side dash trim is in a slightly different position.
8/ Remove trim that runs along the top of the dash just under the windsreen at its bottom. Usually 5x screws (I think, its been a while). Then pull this trim up be carefull not to snap it, watch out if it has a little black dot in the centre you may have to disconnect a wire! ( the later models came with a two piece assembly) You can miss this step, but do so at your own peril!
9/ Remove the foam from beside the speaker grills if they are still there, and yes they do crumble.
10/ You should be able to see a silver screw undernieth the speaker grill, remove this screw from both speaker grills.
11/ Being carefull lift the front of the speaker grill up and pull towards you to remove.
12/ Most speakers have 3x screws coming in at an angle to secure them to the dashboard, remove them and lift the speaker up.
13/ To remove the wiring slightly pry the sides of the connector at the speaker on some, others just have a two pin plug a little further down the wiring. Remove speaker.
This is the best way to remove the front speakers without breaking anything!
Re-fitting is in reverse, obviously!
Kind regards Guy