Try holding a T-50 Torx piece in there, then undo the 17mm nut the other side. If you have fucked the bolt don't panic, there about 2 quid from Ford. BINGO "I THINK IF YOU READ YOUR HAYNES MANUAL" rather than just looking at the pictures"""""" it tells you to hold the Torx end and undo the 17mm nut on the other side" just as mexico_16v says