Whilst researching some Victorian photographs I came across 2 gentleman who had a portable studio on wheels, it was taller on one end (so they could stand up in it?). They may have done instant developing. They used to start on the outskirts of Birmingham and walk every day into the City Centre, where they possibly had a business. I would have liked to have brought this to your attention, but I can't find it again. Anyone help me find it again please?