Thanks for that post David. I was very tempted to buy the tray to fit over the space saver. I definately won't now.
I have cut some 1/4 inch thick plastic, just wide enough to fit into the rebate, to make up the gap to allow the original carpeted floor to still fit flush.
Then taped it down (the plastic, don't laugh) with duck tape, actually it doesn't look too bad.
This will do until i come up with a more quality option.