Gardening is one of those things on which everyone has an opinion... all based on personal experiences. Here, in the U.S., I learned gardenign from a grandfather and he maintained that the longer any sporuts are on potato sets, the better. His reasoning was that the sprout becomes part of the root system and is, therefore desirable for having the set take "root" quickly and efficiently. I always leave as much of the sprout as I can, since they tend to preak off easily. Additionally, cut off a goodly chunk of the potato set to include the sprout and then continue to cut the reaminder into sets just making sure each contains an "eye". Best of luck!