Baked fish on vegetables

Ingredients (4 servings): 2 zucchinis (baby marrows), cut into wedges 2 red onions, cut into wedges 3 tomatoes, cut into wedges ¼ cup pitted black olives ¼ cup (60ml) olive oil 4 x 180g thick skinless white fish fillets (such as hake) 1 small garlic clove, crushed 1 tablespoon lemon juice 1 tablespoon Dijon mustard ½…