To prepare the vegetables place a large saucepan with salted water on high heat and bring to the boil. First, blanche the green parts of the leeks for 30 seconds and then the runner beans for 1 minute until they are just cooked. Set aside. Use a meat hammer to beat the beef to about 0.6mm thickness. Remove any fat and slice the beef into 1.5 x 6cm strips. Put the beef, cornflour, mustard, nutmeg, 20ml (1/2fl oz) vermouth in a bowl and mix well. Add 1 tbsp sunflower oil to large frying pan or wok and place on medium heat. Add only the white part of the leeks to the pan and cook until softened. Remove the leeks from the pan and turn the heat to high. When the pan is searing hot add 1/2 tablespoon oil and the beef mixture and brown the meat, turn the heat to medium and add the white cooked leeks, remaining vermouth (40ml 2(floz)), stock and crème fraîche, salt and pepper. Leave to simmer for 2 minutes. Add the blanched vegetables to the beef to warm through. Remove from the heat and serve with either crushed new potatoes or fresh egg fettucini.