I bought a folding adaptable step ladder / ladder / trestle from B&Q . They are very handy and have had undergone heavy trade usage for a few years. Alas they weren't supplied with treads but two outriggers which slot into the top and foot of the ladder. These outriggers are wider than the steps and when fitted make it difficult to get the steps in and out the vehicle.
I asked B&Q but they were little help. They still stock the steps.
Does anyone know where one can get treads for these steps, or know the name of the company that makes them.