Try to get as much shellfish as you can to make it even more authentic. Chicken stock is great for the flavor. Add it gradually, as you would a risotto. You may need more or less depending on the rice, so just keep adding and use your judgement.
Preheat the oven to 275 degrees F (190 degrees C/gas 5.) Remove the end bits of bone from the chicken legs, then cut them in half. Cut the chicken breasts in half. Coat all the chicken pieces with flour and salt and pepper. Put some oil in a hot large flat pan and brown the chicken legs and thighs, skin side down, turning them to brown them all over. Transfer them to a small roasting tray and continue to cook in the preheated oven for 30 minutes
Add the chicken fillets to the pan and let them brown, then add the chorizo slices. Lay the slices of pancetta over the top. Once crisp, turn the heat down, add the onion and garlic to the pan, and allow to soften. Pour the infused saffron and some of the stock into the pan, and add the smoked paprika and rice, stirring continuously.
Finely chop the parsley stalks and add to the pan. When the rice is almost cooked, add the peas, mussels, prawns and squid, adding more stock if necessary. Cover the pan with foil. When the chicken is cooked, add it to the pan, then add a large handful of chopped parsley leaves. Check the seasoning. Cut the lemon into wedges, place around the edge of the pan, and serve.