My daughter is living in London and sent me a question this morning about several failed attempts to make cream cheese frosting for a birthday cake. She used "icing sugar" as a substitute for American powdered sugar, along with room temperature cream cheese and butter. The problem was the more icing sugar she added the soupier and more liquid the frosting became. It seems a bit odd. Does anyone out there know why this happened? She tried the recipe again, the second time adding half the amount of sugar. The frosting was thick, but not sweet enough and a bit cheesy-tasting. The recipe works fine in the US....?