I hate to rain on the party, but that thing looks like it's designed for the American box-hitch rather than a Euro ball. It wouldn't stay upright on a ball hitch - there would be nothing to stop it falling over.
This is an American towbar with the box that I think this thing is designed to fit in, with the adapter to a ball-type:
Also, nose weight on Euro car towbars is usually no more than 100Kg so 200lbs total which is pushing it for a couple of adults!
Edit - D2 is 75Kg, D3 is 95Kg