Preheat the slow cooker if necessary; see the manufacturer's instructions. Put the onion, red pepper, garlic and tomatoes into the slow cooker pot, then add the wine or stock, saffron, thyme, oil and a little salt and pepper.
Cover with the lid and cook on low for 5–7 hours. Rinse the seafood with cold water, drain and then stir into the slow cooker pot. Replace the lid and cook on high for 30 minutes or until piping hot.
When almost ready to serve, bring a large saucepan of water to the boil, add the pasta and cook for 8–10 minutes or until just tender. Drain and toss with the parsley. Spoon into shallow bowls and top with the seafood sauce.