Warm potato, prawn and scallop salad

Ingredients

• 9 medium kipfler (finglerling) potatoes (700g), halved lengthways
• 150 grams (4½ ounces) green beans, trimmed
• 18 uncooked large king prawns (shrimp) (1.2kg)
• 12 scallops without roe (300g)
• 1/3 cup (100g) whole-egg mayonnaise
• 1 tablespoon water
• 30 grams (1 ounce) baby rocket (arugula)
• Salsa verde
• 1/2 cup finely chopped fresh flat-leaf parsley
• 1/4 bunch finely chopped fresh dill
• 1/4 cup finely chopped fresh chives
• 1 tablespoon wholegrain mustard
• 2 tablespoons lemon juice
• 1 tablespoon drained capers, chopped
• 1 clove garlic, crushed
• 1/3 cup (80ml) olive oil