Heat a large wide-based pan over a medium heat and add a lug of olive oil, the sliced chorizo and the pork belly. Fry for around 10 minutes, stirring occasionally. As soon as the chorizo starts taking on colour and the fat is beginning to cook out of it, add the chopped green pepper, chopped red pepper, garlic, onion, and parsley stalks along with a good pinch of salt, pepper, and the saffron. Fry gently for another 10 minutes, or until the vegetables have begun to soften. Meanwhile, pick through the shellfish and get rid of any clams or mussels that aren't tightly closed.
Add the rice and jarred peppers and keep stirring for a few minutes until the rice is coated in all the lovely flavours, then pour in the tinned tomatoes and 3 1/3 cups (27 ounces)/800 ml stock, seasoning again with salt and pepper. Bring everything to the boil, then turn down to a medium to low heat and stir constantly for about 15 minutes. This combination of flavours will be absolutely beautiful, but you've got to help the dish along by doing your job and making sure each grain of rice gets the same amount of love. So every now and then, stir from the outside of the pan into the middle so you get a sort of pile of rice in the centre, making sure nothing is sticking to the bottom. Flatten the pile out with your spoon, then start the whole process again.
After 15 minutes, the rice should be cooked, but still have a bit of a bite, so add the mussels or clams and the prawns. Cook's Note: You may want to add an extra splash of stock here if the rice looks a bit dry.
Keep stirring, and as the clams and mussels start to open and the prawns begin to turn pink, add your squid and green beans and cook for a further 5 minutes or so.
Discard any clams or mussels that don't open. Stir in the chopped parsley leaves and the juice from 1/2 the lemon wedges, and bring to the table with the remaining lemon wedges on the side.