A SENIOR executive of a large management consultancy firm has been snatched up by the Government's think-tank. Barry Cheung Chun-yuen has been seconded from the American McKinsey & Company for two years. He fills the post in the Central Policy Unit (CPU) left vacant three months ago by Anthony Wong Kin-kwan, who returned to the Hang Seng Bank. CPU head Leo Goodstadt yesterday described Mr Cheung, 35, as a bright young man and disagreed that the appointment would give an advantage to Mckinsey in Hongkong. ''To be involved with the Government, one has to give a lot of their time and effort,'' Mr Goodstadt said. ''I don't think there is any commercial advantage for them.'' The five-member CPU was this year allocated $10 million to give advice to Governor Chris Patten, Financial Secretary Hamish Macleod and Chief Secretary David Ford. Mr Cheung has experience with airport-related projects.