Haydn is a partner and co-head of the Mergers and Acquisitions Practice and a member of the firm's Management Board.

Haydn graduated from the University of the Witwatersrand with a Bachelor of Arts (Honours) (with awards for best undergraduate and honours student in International Relations), Bachelor of Laws, Master of Laws (taxation) and a Higher Diploma in Advanced Company Law (with the award for best student). He joined Webber Wentzel as a candidate attorney in 1993.

Haydn specialises in mergers and acquisitions, general commercial law, insolvency and aviation, representing the South African interests of many of the world's best known companies.

Haydn is also a well known legal figure in the aviation industry, having represented a wide variety of clients, ranging from airport operators, to airlines, ground handlers, aircraft lessors, aircraft engine lessors, aircraft engine maintenance companies, airline associations, the South African Civil Aviation Authority, and the South African Department of Transport.