When I was rallying my 1958 TR3A from 1959 to 1965, I had a back-up light mounted on a 1/4" thick stainless steel bar strip bracket mounted to the top bolt hole for the rear bumperette. The light was a 5" diameter Lucas spot-light. When you are down the wrong road at 3 AM, you want to see as well as you can, to get back on route.
I still have that bracket.