Complex sentence: The first two series were co-produced by Clement and LaFrenais's Witzend Productions and Central Television and the series were broadcast on ITV in 1983-1984 and 1986.
Split into simpler sentences: The first two series were co-produced by Clement and LaFrenais's Witzend Productions and Central Television for ITV. ITV broadcast the series in 1983-1984 and 1986.