Insert a toothpick into each sausage and place in the water. Leave to steep at just below the boil for approx. 30 mins. Warm the butter, sauté the leek for approx. 3 mins., season with salt. Add the potatoes and continue to cook for approx. 3 mins. Pour in the cream and wine, cover and simmer for approx. 15 mins., stirring occasionally. Place the sausages on top of the leek and potatoes, reduce the heat, cover and simmer for a further 5 mins.