Complex sentence: In 1979, he took up another staff post at the MoD, after which he was promoted to lieutenant colonel in 1982 and, until 1985, served as Military Assistant (MA) to the Chief of the General Staff.
Split into simpler sentences: In 1979, he took up another staff post at the MoD, after which he was promoted to lieutenant colonel in 1982. Until 1985, he served as Military Assistant (MA) to the Chief of the General Staff.