Middlesbrough have one of the most expensively assembled squads in the world, according to research. The transfer window was a busy one for Boro as no fewer than eight faces came through the door at the Riverside Stadium. And although Middlesbrough didn’t spend as much as the likes of Chelsea this summer, Michael Carrick has managed to build a side worth quite a lot. So much so, that they are among the 100 most expensive sides in the world. Middlesbrough squad is one of the most expensive in footballAccording to Football Observatory, Middlesbrough have the 100th most-expensive side in the worl…