Defrost the prawns and peel and wash the potatoes. Cook in boiling salted water for about 20 minutes. Wash the peppers, cut into eighths and remove the seeds. Put the pulp on a baking tray. Grill under the grill for about 10 minutes until the skin turns black and blisters.
Remove, cover with a damp cloth until the pods have cooled down. Wash the herbs, shake them dry and chop them. Peel the garlic. Finely dice 2 cloves. Mix mayonnaise and yoghurt, season with salt, pepper and lemon juice.
Stir in garlic and herbs. Drain the potatoes and let them cool down a little. Peel the skin from the peppers and cut the flesh into pieces. Meanwhile peel the prawns and remove the intestines. Wash the prawns, dab dry and season with salt and pepper.
Cut 2 cloves of garlic into slices. Heat the oil in a frying pan. Fry the prawns and garlic for 3-4 minutes, turning them over and taking them out. Clean the rocket and chop a little smaller. Cut the potatoes into slices.
Mix the potatoes, peppers, rocket and aioli in a bowl. Put the prawns on 4 skewers and serve with the potato salad.