I made a receiver shackle mount for the bar at this time and will be sold along with the bar now that it is up for sale.
The number plate bracket was simply another piece of box section that I added some thin sheet steel to two sides to make it a snug fit so it would not rattle at all. You can see how it now sits flush so when the number plate is fitted you would never know that a hitch existed. The holes for the number plate were drilled for 3/16" rivets but the back of the plate was back drilled halfway in with a 1/4" drill so that the rivet would expand in it and sit flush.
The next problem I came across is that it now sits so close to the front cross member that I can not get to the hitch pin. So what I did was to cut off the bend in the hitch pin and then weld a piece of pipe to it which extended all the way to the outside of the frame bracket. A support was placed at the hitch end spaced just far enough away so that the weld holding the two parts together would stop the pin from being fully pulled out.
A small plate was drilled so that the pipe end would pass through it and then welded to it with another small hole in which a thumb screw holds it in place. The frame bracket was drilled and tapped for the thumb screw. Here you can see it with the inside already painted. The outside will be done by my panel beater in baked enamel inside an oven for a professional finish that I cannot hope to achieve with a rattle can!