To make the dressing or marinade whisk together the red wine vinegar, olive oil, parsley, chives, garlic, salt and pepper.
Place the tuna in a shallow dish and pour over half of the dressing. Cover and chill for 1-2 hours to allow the fish to marinate. Toss in the marinade from time to time.
Heat a ridged griddle pan on the hob or a hot barbecue for 5 minutes. Remove the tuna from the marinade. Cook the tuna steaks for 2-3 minutes on each side, depending on how rare you like your fish.
Lay the lettuce leaves onto a large plate and add the lettuce, onion, tomatoes, potato, tuna, beans and anchovies. Drizzle over the remaining dressing then finish by adding the eggs, olives and ripped basil leaves.