Heat the oil in a pan. Saute the onion for 5 minutes, or until soft.
Then add the courgette and cook for another 3 minutes. Then add the peas and sweetcorn and cook for a further 5 minutes.
Meanwhile beat the eggs in a bowl, add water and mixed herbs.
Spread the potatoes evenly across the pan with the vegetables, and pour the egg mixture over. Cook for 5 minutes, or until the omelette is almost set. Meanwhile heat the grill.
Remove pan from heat. Sprinkle half the cheese over the omelette, fold in half and sprinkle the remaining cheese on top. Then brown the top under the grill for about 2-3 minutes, or until golden brown.
Cut into wedges and serve.
This is a great vegetarian dish or add finely chopped chicken or turkey for a meat alternative.