Answer
The answer is the British Darts Organisation (BDO), which is a professional darts organisation based in the United Kingdom. Whitlock, a professional darts player from Australia, was a member of the BDO prior to joining the Professional Darts Corporation (PDC), another major darts organisation. The BDO organises various darts tournaments, including the prestigious BDO World Darts Championship, and has a global presence in the sport.