Place 1/2 cup milk, cream cheese, and garlic in a large pot over low heat. Cook and stir until blended. Mix in soup, spring onions, carrots, corn with liquid, potatoes, parsley and remaining milk. Season with black pepper and cayenne pepper. Simmer 25 minutes. Do not boil.
Mix the prawns, scallops, crabmeat, and calamari and continue cooking 10 minutes, or until seafood is opaque.