Very nice work indeed Andy! not sure what the small tank is, but I'll see if I can find out. Note that the blast tubes at the gun muzzles, which mate with the cowling troughs, were normally painted the interior colour, RLM02/66. Also, most photos of the exhausts show the first stub to be painted, colour shots suggesting RLM02. I'm guessing they might all have been painted at one time, but hot exhaust gases burnt off the paint on all but the front one.