Crab and Grapefruit Salad

Ingredients

• 4 medium grapefruit
• 2 tablespoons mayonnaise
• 1 tablespoon finely chopped mango chutney
• 2 teaspoons Dijon mustard
• 1 teaspoon sesame oil
• Salt and freshly ground black pepper
• 400 g crabmeat, picked over to remove any pieces of shell or cartilage
• 1 head witlof (Belgian endive/chicory), cut crosswise into thin strips
• 100 g watercress, tough stems trimmed
• 1 head lettuce, such as mignonette, separated into leaves, for serving