1. Wash and peel the potatoes, cut them into chips about 1.5cm (¾ in.) thick. Soak them in a bowl of cold water for half an hour, rinse and pat dry with a tea towel. If you have the time, leave them out on paper towels for a while to dry completely.
2. Skin and pin bone the fish fillet and cut it in two portions.
3. Place the flours and the baking powder in a large bowl, add the honey and gradually stir in the lager. The batter might be a bit lumpy but if you let it chill for half an hour, the lumps will dissolve. Prepare extra rice flour on a shallow dish.
4. In the meantime heat the groundnut oil in a chip pan or a deep-fat fryer to 130C/250F. Plunge in the chips and cook until they are slightly coloured, about 10 minutes. Lift them out with a slotted spoon and place on a cake rack with some paper towels underneath it. Let them cool completely.
5. Heat the oil for the fish in another pan – or cook in one but then the chips will have to stand for a few minutes, putting them in a warm oven is a good idea. The second dip will take only a few minutes, until they colour and crisp to your liking, in oil at 190C/375F.
6. Heat the oil for the fish to 220C/425F. When you’re ready to cook, season it with salt and pepper, dredge each portion in the rice flour and dip in the bowl with batter. When it’s covered completely, lower each portion into the oil. Don’t forget to drizzle in some batter on its own, for scraps – arguably the best bit of fish and chips.
7. Cook the fish for 3 – 4 minutes until light golden brown, then turn over to the other side and cook for another minute or so. Lift the fish from the oil and drain briefly on a paper towel before serving with the chips and cooked garden peas.