Complex sentence: For a time he ran his own public relations agency, with clients including Pan Books, Topic Records, and Billy Smart's Circus; and worked as a record producer for the Transatlantic, Island and Sonet labels, and as a concert promoter.
Split into simpler sentences: For a time he ran his own public relations agency, with clients including Pan Books, Topic Records, and Billy Smart's Circus. He also worked as a record producer for the Transatlantic, Island and Sonet labels, and as a concert promoter.