A friend uses a remoska from Lakeland in their camper - loves it and it's miserly with electricity, lidded so no smells and you can do all sorts in them, they are expensive though. I recently bought a double skillet, non electric for camping and have tried it at home with great results, even baked a cake! And being non electric can use it anywhere. Quite big though, but they do two sizes. There are reviews on here about both of these I think.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.