You can make yourself a sturdy cover. Get you some 1/8 inch aluminum, probably diamond plate, so it will be a non slid surface. Then, cut it out, so that it is 2 inches, longer, and 2 inches wider than the recessed pedal. So, when you cover the hole, it will hold on 1 inch all the way around. Now, get you some 1 inch angle, could probably be as thin as 1/16 inch or so, and put it underneath, 1 inch in from the sides, so it provides a lip. Now, drop that in your hole, and the lip will keep it solid and snug, and you will have a nice, slip in removable cover. The lip could be riveted on, or you could put flat head stainless machine screws in.
Does this make any sense?