Cut the potatoes into large wedge-sized chips, all roughly the same size. Rinse under cold water to wash away the starch. Bring a large pan of salted water to the boil with the vinegar, carefully submerge the chips and simmer gently for 6-8 mins, or until tender. Lift the chips out of the water, or carefully drain without breaking them, and leave to cool on a baking tray, uncovered, in the fridge for 30 mins. Can be done up to two days ahead.
When you’re ready to cook, heat oven to 220C/200C fan/gas 7. Tip the chips into a bowl and heat the oil in a roasting tin for 5 mins. Once the oil is hot, carefully add the chips and use a fish slice or tongs to turn them in the hot oil. Bake for 40 mins, then turn them and scatter over the parmesan. Continue to cook for another 20-30 mins until golden and crisp.
For the dips, combine all the ingredients for each dip (see below) in separate bowls and stir, seasoning to taste. All the dips can be made the day before; cover and chill until needed. Remove the chips from the oven, drain on kitchen paper, then sprinkle with a little salt and the parsley. Serve alongside the dips.For the harissa yogurt dip 200g tub Greek yogurt 1 tbsp harissa (rose harissa is good if you can find it) small handful parsley, choppedFor the lemon & garlic dip150g mayonnaise1 lemon, zested2 garlic cloves, crushed½ tsp cracked black pepperFor the Marie Rose dip200g mayonnaise60g ketchup5 drops Worcestershire sauce5 drops Tabasco¼ tsp smoked paprika½ lemon, juiced