Cook the eggs in boiling water for around 7 minutes. Drain and cool under running water. Peel and quarter.
Cook the potatoes in lightly salted water until tender. A couple of minutes before they are fully cooked, add the beans to the pan. Drain then cool under running water.
Quarter the potatoes. Wash the little gem lettuce and pat dry to remove as much water as possible.
Quarter and place on a large serving platter. Scatter over the beans and potatoes.
Quarter the tomatoes and add to the salad. Arrange the eggs on top.
Drain the tuna and add to the salad.
Top with anchovy fillets and, finally, add the black olives.
Use a fork to whisk together all the dressing ingredients and then drizzle over the salad.