To make the beer batter, sift the flour and cornflour into a bowl. Make a well in the centre and add the lager. Whisk the liquid ingredients together and then gradually whisk into the flour mixture until you have achieved a smooth batter and store in the fridge.
Cut the fish into pieces if desired or leave the fish in 4 large piece.
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.
Wash and peel the potatoes.
Cut the potatoes into thick cut chips and store in water until required.
Deep fry in hot oil 180°C until fully cooked.
Serve the fish and chips in little newspaper cones , and a wedge of lemon and enjoy.