ROME (Reuters) – The multi-billion euro buyout bid for infrastructure group Atlantia proposed by the Benetton family and U.S. fund Blackstone cleared the last major regulatory hurdle on Thursday after an authorisation by the Bank of Spain. The Benetton family, which already owns 33% of Atlantia, and Blackstone still need to get one final go ahead from Italy’s market watchdog Consob before they can officially launch the bid on the stock market. The Benettons and the U.S. fund, who have joined forces through investment vehicle Schema Alfa, have proposed a 58 billion euro buyout offer for the air…