Takom kit. Inspired by, but not directly copied from, the photo behind. It seems to have been through muddy water or watery mud rather than thick mud. I liked the fuel cans and other stowage all over the roof, and chose various period colours for the different fuel brands as well as some khaki ones.
It did take some nerve to do as I really liked the base brown finish, now largely hidden, and it could have gone badly wrong. The mud from the top was a concern. Surface tension meant that paint drips under their own weight would need to be too big. This was largely done with small drops placed and chased down with a dry airbrush.