Cut the eggs neatly into quarters. Pull the heads off the prawns and discard. Peel off the shells and place in a pestle and mortar. Pound thoroughly to extract every bit of flavour and juice from the shells. Strain the resulting liquid and mix it with the olive oil, garlic and parsley and lemon juice. Mix half this dressing with the mussels and set aside. Cut the peppers in half and remove all the seeds and cores. Grill the peppers for about 3 minutes on each side, then rub off the skin. Lay the peppers on a serving platter and drizzle over a little of the prawn-flavoured dressing. Arrange a layer of hard-boiled eggs on top of the peppers, then arrange the mussels on top of the eggs. Cover with the prawns. Drizzle the remaining dressing over the prawns and chill until required.