I watched that show BECAUSE my long-past grandparents were like that.
They thought my dad was an oaf and us offspring needed constant nagging to behave like whatever upper-middle-class citizens my grandparents imagined we should resemble. But this show reminded me so well of them!
It's also nice that Brit-coms show normal "council housing" and average-ugly people and not 95th-percentile mansions like American TV.