The children, especially during the earlier series, could only act for 30-45 minutes at a time. Often when they were out of shot, the directors would often stand in their place so that the adults would know where to look.
Although some of the speech is written, a large amount of the interaction (especially between the children) is completely improvised.
Hugh Dennis and Claire Skinner played on-screen couple Pete and Sue. They became a couple in real life in 2017 after both their marriages ended in divorce.
Hugh Dennis' real first name is Pete (short for Peter), just like the character he plays on the show. He uses his middle name Hugh professionally because there was already a Peter Dennis registered with Equity (the British actors' union) when he started his career.
Both of Sue's bosses throughout the series, Veronica and Tyson, are neither heard nor seen at any point in the series.