This should have been a half hour job. Two simple wooden supports which slot into the ends of the trailer frame, to hold the lighting board when there is no boat on the trailer. Only one of the tightening bolts had rusted solid. When I turned it with a pipe wrench, the threaded insert broke loose from a poor weld and just turned beneath the bolt. In the end I had to saw off the plastic top and the use a powered multi tool to saw through the bolt. Eventually achieved after two hours lying on my back under the boat. Spent half an hour in a sauna after to bake the aches out of my back.