Just checked, and this may help.
The drawer is held in by a couple of spring levers at the back of the drawer, one on each side. (see the pics below, No1)
Pull the drawer fully out, and then insert a couple of screwdrivers or other flat items into the top corners (you may need to grovel on the floor and look underneath the seat to see where. ) The levers are held in place by the stops on the underside of the drawer runners (see pic no2)
Press down with the screwdrivers and pull the drawer towards you, this should disengage the levers from the stops, and drawer should slide out for you.
Replacing the drawer is simple. as the levers are shaped to push back over the stops without any tools.
Hope this helps... (and that the pics upload!!)