A mint and very clean replacement was £60 from eBay and came with the speakers, grilles and all trim pieces, handy as mine was missing some.
FITMENT:
1. Remove the rear-seat squab by pulling the front edge up sharply at either side and sliding it forward.
2. Remove the 3 bolts holding the bottom-end of the rear seat-belts to the body using a T45 Torx-socket.
3. Remove the rear-seat back-rest by undoing the 2 bolts holding the bottom brackets in place using a T45 Torx-socket and lifting it vertically up off the upper brackets.
4. Remove the 5 plastic-clips holding the leading-edge of the parcel-shelf by prising the centre-pin out with a flat-screwdriver [or ideally a trim-tool] and then prying the clip out.
5. Loosen both of the C-pillar trims. They are only clipped on and should pop off easily enough at the bottom. They do not need to be completely removed, just loose enough to allow the lip at either side of the parcel-shelf to slide in and out.
6. Slide the parcel-shelf forward partially, pop the seat-belts through the apertures and disconnect both speaker wires. The parcel-shelf can now be fully removed.
7. Swap trims/speakers over to new parcel-shelf.
8. Reverse steps 1 - 6 to refit.