Celtic inflicted damaging blows on Rangers during May, ending their Scottish Premiership dreams and beating them in the Scottish Cup final. It has left the Ibrox side with serious questions to answer this summer with many expecting there to be a high turnover of players after multiple failures. However, they aren’t in the best shape to deliver that after the exit of their CEO James Bisgrove, which was announced in a surprise statement on Thursday. The Scottish Sun reports Bisgrove has quit the club and is moving to Saudi Arabia. It’s a sudden switch said by the paper to have left the Ibrox hie…