Clean the mussels and clams by washing under cold running water, discarding any open shells that don’t close when tapped.
Prepare the barbeque with the baffle in upright position and heat to approximately 180-200°C for baking.
Sit a large paella pan or skillet on top of the grill plate. Add a really good glug of olive oil and sauté the onion until it has softened, stirring continuously.
Stir in the garlic and rice for a minute or so until the rice is coated in the oil, then add the wine, saffron, paprika and enough stock to cover the rice (about two-thirds of the measured quantity). Stir well and bring to a simmer. Allow to gently simmer with the lid up and cook for about 10 minutes, stirring occasionally to prevent the rice sticking to the bottom of the pan. Add some more stock if it is being absorbed too quickly.
Stir in the mussels, clams, squid, peas and peppers and season with salt and pepper. Arrange the whole prawns on top and pour over the remaining stock. Cover with the barbeque lid and leave to about 10–15 minutes, until the rice is tender and the seafood is cooked through (the mussel and clam shells should be open).
Sprinkle over the parsley and place the lemon wedges on top. Serve the paella straight away.