Start by making the chips. Make sure the potatoes are washed but the skins are left on. Cut them into chips, roughly 1 centimeter thick. Blanch in hot salted water till cooked through but still holding their shape, about 8 minutes.
Place the chips on oven tray, drizzle with oil and season. Let this cook for about 20 minutes.
Place the peas in a pan with enough water to cover and bring to the boil. Once cooked drain and add the butter, salt, pepper and a splash of vinegar. Give them a good mash.
Remove the leaves from the mint and finely chop, add into the pea mix, stir and set aside.
Heat the oil so it starts getting up to temperature for deep fat frying. Place the flour and soda water in a shallow bowl with some salt and mix together. Using a little extra flour, dust the fish and dip in the batter letting any extra drip off. Once the oil is hot enough, first place the tortilla wraps in the oil for a couple of minutes just to colour and harden slightly ready to have as taco shells.
Remove and place on a kitchen roll. Then add the fish to the oil until crisp and cooked through. About 6 minutes, turning halfway through.
To make the tartare sauce, finely chop the herbs, capers and jalapeños. Add this to bowl with the mayo and lemon juice.
