Complex sentence: Whitlock competed at the English Championships in March as the defending AA champion, winning gold on pommel horse with a score of 16.4, however he struggles significantly on the other events and did not compete on vault, his last event.
Split into simpler sentences: Whitlock competed at the English Championships in March as the defending AA champion. He won gold on pommel horse with a score of 16.4, but struggled significantly on the other events and did not compete on vault, his last event.