Complex sentence: The Sioux were replaced with 12 Westland Gazelle AH.1s in 1974/5, and in 1982, six TOW-equipped Westland Lynx replaced the Scouts.
Split into simpler sentences: The Sioux were replaced with 12 Westland Gazelle AH.1s in 1974/5. In 1982, six TOW-equipped Westland Lynx replaced the Scouts.