Attaching the number plate to an ARB bar

The following are some pictures of the installation.

The US number plates are larger than the Oz ones, this requires a little modification.

This is the front view - nothing out of the ordinary.

This is the back view. To fit the plate so it wouldn't slide off, I just cut a length of aluminium bar and drilled holes that mate up with the holes in the number plate. The bar acts as a large washer. That's all there is to it. It will deform if hit, so what...