Complex sentence: Jolly was the most senior serving psyops officer in British Defence with the rank equivalence of a Major-General up until his departure in the summer of 2016 to take up an unspecified role in international defence.
Split into simpler sentences: Jolly was the most senior serving psyops officer in British Defence with the rank equivalence of a Major-General. He left Defence in the summer of 2016 to take up an unspecified role in international defence.