Wash and scrub the potatoes. Leave the skins on and slice into thick fries, approximately 1 centimetre thick. Rinse under cold water and pat dry.
Heat the oil to 140C. Carefully add half of the fries to the hot oil and cook for 5-6 minutes until soft but still pale. Drain on kitchen towel while you repeat with the second batch. Spread them out to cool for 10 minutes and heat the oil up to 180C. Cook the fries at the higher temperature until they are golden brown. Do this in batches if necessary.
Heat the gravy while the fries are cooking.
Drain the fries briefly on kitchen paper then transfer to a large mixing bowl. Toss 1 teaspoon of sea salt flakes into the fries, then pour in enough hot gravy to just coat them - use tongs to toss it all together. Sprinkle in the cheese curds and combine again, then serve immediately.