Cut your MSC certified white fish into strips approximately one inch wide by four inches long.
Crush the cornflakes in a food processor or with a rolling pin in a freezer bag. Place into a bowl.
Beat the egg with one tablespoonful of water and place into another bowl.
Dredge the fish strips first in the flour, then the beaten egg and then coat in crushed corn flakes. Set aside on a plate and repeat with the remainder of the fish. It's easier if you use half the cornflakes at a time because they will start clumping together with the egg (as will your fingers - wash your hands regularly to make it easier).
Chill the fish fingers for 15 minutes in the fridge while you prepare the potatoes.
Cut your potatoes in half lengthwise, and then half again. Carefully cut each quarter in half again, so you get eight potato wedges from each potato.
Drizzle with sunflower oil and the spices, and coat well.
Transfer to a baking tray and bake in the oven for 35 minutes, turning halfway.
To prepare the tartare sauce, combine all the ingredients in a small bowl, stir, and chill in the refrigerator until needed.
Bring the sunflower oil to 176-190 C. Make sure you use a thermometer for this! If the oil isn't hot enough you won't get a crispy coating, and if the oil is too hot you'll risk it catching fire. A thermometer is essential! NOTE - DO NOT LEAVE HOT OIL UNATTENDED!
Deep fry the fish fingers, in small batches, for approximately one minute each. Drain on kitchen towel and bring the oil back up to the correct temperature before cooking the next batch.
Serve immediately with the potato wedges, tartare sauce, garden peas and a lemon wedge.