Complex sentence: Between 1983 and 1987, Alien Sex Fiend had twelve more singles on the independent chart, all but one of which reached the top 20, and also had five albums reach the top 20 on the UK independent album chart.
Split into simpler sentences: Between 1983 and 1987,12 more Alien Sex Fiend singles reached the independent chart, all but one of which reached the top 20. Five of their albumss reach the top 20 on the UK independent album chart.