By Jamie Spencer Chelsea manager Mauricio Pochettino has called on the club to sign a set-piece specialist, namedropping West Ham United’s James Ward-Prowse as an example of the benefit. The Blues have spent an unholy amount of money on new players since Todd Boehly led a 2022 takeover, but Pochettino has a squad struggling to stay in the top half of the Premier League. The Argentine has now identified a free-kick expert as a key component that is lacking. “We work a lot on set-pieces. We have a group of analysts. After that, it is about the quality of the player, about the takers,” he said ah…