Grey Global Group’s Grey Worldwide is in negotiations for the estimated $80-100 million European ad account of Volkswagen’s Seat, sources said. The Barcelona-based business was previously held by CCG’s Bates Worldwide. Martin Sorrell, CEO of WPP (which acquired CCG in August), had tried to retain the Seat account, but it was in direct conflict with WPP’s global Ford Motor business, sources said. Grey chairman and CEO Ed Meyer could not be reached. A Grey rep declined comment, as did a WPP rep.