Thought this might be of interest - I am reluctant to loose my rear bumper so got these plates cut from 1.5mm thick stainless, and 4.5mm thick mild steel which I had cadmium plated after bending and drilling. I had to drop the tow bar assembly to weld the mounting brackets on. I also took the opportunity to relocate the tow bar electrical plug.
Photos 1 and 2 show the before, 3 shows the the 1.5mm thick laser cut plate, 4; 5; 6 and 7 show the finished product.