Place the hake in a shallow dish, then sprinkle over the lemon juice and leave to marinate for 30 minutes covered with cling film in the fridge.
To make the tartare sauce, mix all ingredients together and season with salt and pepper. Place in a small bowl and cover with cling film, then chill until needed.
When ready to cook, preheat the oven to 200⁰ C. Line a baking sheet with parchment paper.
Cut the potatoes into thick chips. Bring a pan of salted water to the boil and blanch the chips for 5 minutes. Drain and dry well on kitchen paper. Place the chips onto two baking sheets and toss in the rapeseed oil, then arrange in a single layer and season with a little salt.
Put the flour on a plate and season with salt and pepper. Lightly beat the egg and place in a shallow dish. Mix together the breadcrumbs, lemon juice, parsley and sesame seeds in a shallow dish. Dip each hake fillet into the seasoned flour, shaking off any excess, then dip in the egg. Finally coat each fillet evenly in the flavoured breadcrumbs and place on the lined baking sheet. Lightly spray with the olive oil.
Put the chips into the oven and cook for 30 minutes. Place the coated fish fillets in the oven and cook for another 15-30 minutes, until the fish s cooked through and golden brown and the chips are nicely golden.
Divide the fish and chips between four plates and add a small dish of the tartare sauce to each one along with a lemon wedges. Serve with separate bowls of green salad.