Mr. Thornhill is currently the Managing Partner of the firm George Walton Payne & Co., the firm's representative at meetings of MacIntyre Strater International. He is also a member of the International Tax Planning Association (ITPA).
Mr. Thornhill is a Fellow of the 'Institute of Chartered Secretaries and Administrators in Canada' (ICSA) and is the Facilitator for Barbados in respect of the Corporate Law courses. He has led seminars for ICSA students in Barbados as well as Toronto, Canada.
He is a Charter Member of the Congress of Fellows of the Center for International Legal Studies. The Center for International Legal Studies is a non-profit research, training, and law publications institute, established and operating under Austrian law and with its international headquarters established in Salzburg, Austria. The Center has operated since 1976 in Salzburg.
Mr. Thornhill has written several articles, including "Partial Convergence of Domestic and Exempt Insurance" published in The OFC Report 1999, the report of offshore financial centres and services; the Barbados Chapter for the Sweet & Maxwell publication "Aircraft Finance: Registration, Security and Enforcement"; he has contributed the Barbados chapter for the Asset Protection Journal, a publication edited by the Boston Law Firm Alexander Bove, JR., P.C. His most recent publication is the Barbados Chapter for the volume entitled "International Taxation of Low-Tax Transactions", published by the Center for International Legal Studies. He has recently concluded his research and has written the Barbados Chapter for another Sweet & Maxwell publication called "Aircraft Liens & Detention Rights"
He served as a member of the Exempt Insurance Review Commission, a commission set up by the Government of Barbados to review the Exempt Insurance Legislation. He also served as a member of the Advisory Committee on International Business & Financial Services. The main focus of the Advisory Committee is the repositioning and enhancing of the International Business and Financial Services sector of Barbados.
Mr. Thornhill is also a member of the London Court of International Arbitration - North American User's Council.
Mr. Thornhill has made presentations in the United States of America, Germany, United Kingdom and Hong Kong on the use of Barbados as an International Financial Services Jurisdiction. He has also made presentations locally on matters of corporate and commercial law.