Peel and dice the potatoes and dry them on some kitchen paper; then trim the leek top and bottom.
Slice it in half first lengthways and then across into ¼ inch (5 mm) thick strips, wash carefully in plenty of cold water, and drain and dry thoroughly. In a frying pan, about 6 inches (15 cm) diameter, heat the oil and add the diced potato. Cook gently for about 10 minutes, stirring frequently.
When the potato is just tender, add the chopped leek and diced bacon to the pan. Stir well, cover with a suitably sized lid and cook over a low heat for a further 5-8 minutes.
Meanwhile break the eggs into a bowl. Season well with salt, freshly milled pepper and mixed herbs. Stir to blend the eggs together, then pour the mixture over the contents of the pan. Shake the pan and cook over a low heat until the underside of the omelette is cooked and lightly golden. Meanwhile preheat the grill, then transfer the pan to the grill and continue to cook gently until the egg on the surface is just set. Cut the omelette in half or quarters and serve on warmed plates. This is nice with a crisp salad.