To make the batter, sift the flour and cornflour into a bowl. Add the dried yeast and Make a well in the centre. Whisk in the beer or soda water into the flour mixture until you have achieved a smooth batter. Cover with cling film and leave to settle for 30 minutes at room temperature.
Cut the potatoes into thick cut chips and store in water until required.
In the meantime, prepare the pea purée.
Melt the butter in a saucepan over a medium heat. Add the onion and garlic and fry for 30 seconds until softened. Pour in the cream and wine and bring to the boil. Add the peas and simmer for 3–4 minutes, until they have softened. Remove from the heat, season with salt and pepper and stir in the mint. Slightly crush the peas with a potatoes masher to create a chunky pea sauce and transfer to a bowl.
Cut the fish into pieces if desired or leave the fish in 4 large piece.
Preheat the deep fat fryer to 180˚C and preheat the oven to 120˚C if using.
Dust the strips of fish in a light coating of flour and then dredge in the batter, shaking off any excess. Deep-fry for about 5 minutes or until cooked through and golden brown. You may have to do this in batches depending on the size of your fryer. If you are cooking larger pieces of fish start cooking it in the fryer and then transfer to the oven to finish cooking.
Then, Deep fry the potatoes until fluffy and cooked through.
Serve the fish and chips in little newspaper cones, a wedge of lemon and peas puree.