Harry Kewell’s short and sweet spell at Celtic can go down as a complete success. He was appointed by former manager Ange Postecoglou in the summer of 2022 to add big-time quality and experience to the Bhoys coaching staff after a stellar playing career at the highest level. His management and coaching career up to that point hadn’t seen much success but the Celtic opportunity was a chance for him to reset and refocus. Kewell was popular with players and staff, becoming a key part of the group that delivered a superb treble during the 2022/23 season. Now, having left the Bhoys late last year t…