In football there are two main reasons why transfer policy goes badly. The first involves knowing what you want, but not having the means to get it, and often settling for less. This is a pretty simple dilemma that all but about seven of Europe's top teams will be familiar with - a case in point would be Spurs wanting Sergio Agüero in 2012, but through lack of means ending up with a 32-year-old Louis Saha. Ok, that was a rather extreme example. Most clubs have certain constraints to work...