That picture isn't really correct. The Phillips-head bolt on the hinge on the left is supposed to hold a little bent over metal keeper. The head of the hinge pin should be on the other side, and the keeper keeps the head of the hinge pin from backing out. That way, you don't need the cotter pin for that hinge pin. This is nice, because the cotter pin is usually partly interfered with by the seat cover, and can be difficult to get in and take out.
I probably have what you need, but I'm in the U.S. Let me know if you are interested.