Chicken and leek soup (cock-a-leekie)

Ingredients

• 8-10 pieces chicken legs, bone in
• 2 large white onions, chopped
• 2 carrots, chopped
• 2 celery sticks, chopped
• 2 large stalks leeks, sliced
• 1 small red capsicum, chopped
• 1 small orange capsicum, chopped
• 1/2 cup full cream
• 1 litre chicken stock
• 1 litre water
• salt
• freshly ground black pepper
• 1 teaspoon rubbed thyme
• 3 tablespoons butter