Celtic have done some excellent work over the first half of this season in extending the contracts of the majority of their best players this season. When Ange Postecoglou left to join Spurs, speculation was rife that many of the players he brought to Celtic Park would join him in London. However, Celtic worked hard to ensure that didn’t happen and have tied up the likes of Kyogo Furuhashi, Daizen Maeda, Cameron Carter-Vickers and Matt O’Riley to new long-term deals. However, one of the constants Celtic’s successes over the last two seasons, Joe Hart, sees his contract expire at the end of the…