Add saffron to the hot stock and leave to infuse for 20 minutes. Bring back to a simmer and keep hot for the risotto.
Heat oil over medium heat in a large, heavy-based saucepan. Cook onion and garlic for 8 minutes, stirring occasionally, until onion is golden. Add anchovies, bay leaves and barbecue marinade. Stir for 2 minutes or until anchovies break down. Add rice and stir until well coated. Add wine and stir for 30 seconds. Stir in chopped tomato.
Reduce heat to low and keep at a simmer. Stirring continuously, add 5 cups of hot stock, a cupful at a time, waiting until each one is almost absorbed before adding the next. The rice should still be slightly firm.
Add the seafood and remaining cupful of stock. Cook, stirring occasionally, for a further 5 minutes or until the mussels have opened and the other seafood is just cooked. Transfer to a serving dish and top with olives and parsley.