Put the mussels, clams and cockles in a pan with ¾ of the wine and steam the shellfish open for 3-4 minutes. Discard any that remain closed. Strain, reserving the stock for the risotto.
Heat the olive oil in a large pan and cook the onion, garlic, safrron and crumbled chilli gently until softened. Add the rice and continue to fry until it is translucent. Pour in the remaining wine and allow it to evaporate and be absorbed by the rice. Add the squid and the monkfish or gurnard. Add a ladleful of the reserved stock a little at a time, and let it be absorbed by the rice. Continue to add stock and stir the rice. After 10 minutes add the langoustines and the shell-on prawns and continue to cook, adding a little more stock for a further 5 minutes. Add the mussels, clams and cockles, and the peeled prawns and cook for a further 2-3 minutes.
Add the parsley and remove from the heat. Whisk in the butter and leave to stand for 2 minutes before serving. Finish with a squeeze of lemon.