Drain the soaked chickpeas, put them into a pan and cover with fresh cold water. Bring to the boil and simmer until the skins begin to crack and they are tender – about 40 minutes – adding 1 teaspoon salt to the pan 5 minutes before the end of the cooking time. Drain and leave to cool.
Cut the body pouch of each squid open along one side and score the inner side with the tip of a small, sharp knife into a fine diamond pattern. Then cut each pouch lengthways in half, then across into 7.5-cm pieces.
Stir the tomatoes into the chickpeas with the lemon juice, 4 tablespoons of the olive oil, the chilli, garlic, flat-leaf parsley and some salt and pepper to taste.
Heat 1 tablespoon of the remaining olive oil in a large frying pan over a high heat. Add half the squid pieces, scored side facing upwards first (this will make them curl attractively), and half the tentacles and sear for 30 seconds, then turn them over and sear for another 30 seconds until golden brown and caramelized. Season with salt and pepper and remove from the pan. Repeat with the remaining tablespoon of olive oil and the rest of the squid.
Place the merguez in a lightly oiled frying pan. Prick the merguez & cook - covered - over a medium heat for 10 minutes. Slice into 1cm rounds.
Return all the squid to the pan with the merguez and toss together over a high heat for a further minute.
Briefly toss the rocket leaves through the chickpea salad and spoon onto 1 large or 4 individual plates. Top with the sautéed squid & merguez.
Serve immediately with plenty of crusty bread.