This is the often missing or unknown.. front and Center REAR of the bonnet / hood mounted Center adjustable bump stop.. located on the inside last fold of the hood and is adjusted to help keep the center of the hood.. at the .. from bouncing or sinking .. which in turn also makes the hinges gab a bit too.
Size is 25mm hex head, 23mm wide & approx 46mm long.
Tip: Good idea to put a bit of white grease on it to help the bonnet to slide across it and not jam.