Complex sentence: At the end of 1979, Foster and Allen released the single, "A Bunch of Thyme" in Ireland, and it entered the Irish chart and became their first No.1 single, and stayed on the chart for 40 weeks.
Split into simpler sentences: At the end of 1979, Foster and Allen released the single, "A Bunch of Thyme" in Ireland, and it entered the Irish chart. It became their first number one single, and stayed on the chart for 40 weeks.