Ok guys it didn't turn out too bad at all so thought I would share with you.
Firstly I removed the storage unit from behind the seats.
I then removed the "cubbyholes" these are fixed with 3 torx screws but also hot glued at the front, remove the glued area carefully to prevent damage to the thin plastic edge.
I then made some templates from 3mm ply I had lying around to mount the 3.5" speakers I bought from ebay for £57 quite reasonable I thought!
Then I covered the mounts with some alcantara I had left over from previous interior mods I carried out
One side in place
And now in position in the car
Sorry for the iphone quality pics, not sure whether to purchase the speaker grills yet as they cost more then the speakers, but will give it a factory look.
Just got to wire them in this weekend and job done, not bad for less then £60!
Might do the doors now