In a saucepan, place the potatoes cubed and fill with salted water.
Bring to boil and simmer for five to seven minutes to part boil the potatoes. Remove from the heat and drain in a colander.
Prepare the vierge sauce. In a bowl, combine the diced tomato, shallot, lemon segments, and fresh herbs. Season with salt and pepper and stir to combine. Keep aside until required.
Heat a sauté pan over medium heat. Drizzle some olive oil and place the cod pieces, flesh side down. Cook for five to eight minutes, turning the fish over once. Season the fish with salt and pepper.
In the meantime, in a bowl, Place the garden leaves. Squeeze the second half of lemon juice over with a drizzle of olive oil and seasoning. Toss to combine.
Serve with the vierge sauce. And the salad leaves.