Going toe-to-toe with Kellie Harrington is rarely advisable.  I met the recently retired double Olympic gold winner at the opening night of Flight Club on Dublin’s Dawson Street last week.  Harrington has a warm personality but she retains the competitive instincts of a champion boxer. Darts is however a great leveller, where even a journalist has a chance. I managed to beat her in the first game when she was distracted by well-wishers. But she hit her stride as the night went on and the venue packed out with 500 people playing interactive darts, including well-known faces from the worlds…