1) Saute chopped spring onion and garlic in butter until tender. Stir in flour, stirring until well blended. Slowly add the fish stock, continuing to cook until smooth and bubbly. Slowly add cream and milk. Stir in crabmeat. Add sherry, lemon-pepper seasoning, salt and white pepper.
2) Simmer soup until piping hot; adjust seasoning (sherry, salt, and pepper), to taste.
Serve in bowls topped with cheese and chives.