Peel potatoes, cut into chips, then put in a medium pan. Cover with water, add a pinch of salt and bring to the boil over a medium heat. Cook until chips are parboiled. Remove from heat and drain. Line a tray with a tea towel. Arrange chips in a single layer on prepared tray and refrigerate until cool.
Heat vegetable oil in a deep-fryer to 130°C. Line a tray with paper towel. Fry chips, in batches, for 4-5 minutes or until texture is slightly dry. Remove with a slotted spoon and put on prepared tray.
Increase heat to 180°C. Fry chips, in batches, for a further 3-4 minutes or until golden and crunchy. Drain,
then season with salt.
Rub olive oil on each side of fish, then season with salt and pepper. Heat a large non-stick frying pan over a medium-high heat. Add fish and cook for 2-3 minutes on each side or until cooked through. Remove pan from heat, cover loosely with foil and set aside for 5 minutes.
Put lemon rind and salt flakes in a small bowl. Rub together with your fingers until combined. Serve fish and chips with lemon salt, aioli, salad and lemon.