i bought dozens of the Aust workshop trailers when they were sold,mainly because at the price they had two new tyres and wheels...No one wanted them ,as they were just on the limit for brakes in Qld,so theoretically,you couldnt carry anything in them.......and the army had stripped all the towrings off them......Not a big deal in those days,I just fabricated a standard coupling to fit,.....All i remeber about them is they were made by the Govt Aircraft Factory...(GAF)......i dont thing there was a great deal of ally either ,more steel and plywood........initially ,I couldnt sell them,but after all the wheels and tyres were gone,there was interest in them....maybe couple of years later..........The frame was a central steel tube,with a couple of steel crossmembers,flange at top folded full width,floor bolted on .