He has been with Tarsus since its launch in 1998; prior to which he held senior management positions at Blenheim Group plc and after its takeover, United Business Media plc. He is a past Chairman and remains a Director, of the Association of Event Organisers (AEO) as well as past Chairman of the Events Industry Alliance. Having been the first international board member of the US-based industry trade body, Society of Independent Show Organizers (SISO), he now also currently serves as SISO Chairman. In addition, Douglas was a founding member of the International Organiser Network (ION), a joint AEO and SISO group.