Complex sentence: The losing team return to the boardroom and are subjected to a detailed review of their performance by Sugar and his advisers, who deliver any criticisms they have of the PM and single out any team member whom they feel performed poorly.
Split into simpler sentences: The losing team then return and are subjected to a detailed review of their performance by Sugar and his advisers. They deliver any criticisms they have of the PM and single out any team member whom they feel performed poorly.