Throw out the 2 mm ribbed mat in the load space if it hasn't already torn. Get some ribbed rubber mat material from clarke rubber or purple pig of 6 mm, thickness or more and place it on the inside of the vehicle in the load space. Use a bit of contact adhesive to hold it onto the sponsons/guards horizontal and vertical surfaces. Much easier and cleaner than spraying stuff under the vehicle and it protects the load space.