I am doing some modelling with small 3ft gauge prototypes in 21mm gauge. Alex Bingley has 3D printed a small wagon frame, based on a Torrington & Marland 10ft length wagon [Ted Davies' drawing] but would also suit the Southwold open wagons, using Slaters 14mm wheels. I'll take delivery at the Trent Valley show and he's happy to print them for anyone else.