If you want to see some other sitcoms showing 'typical' family life, you could see 'Outnumbered' for a middle-class professional family, or 'The Royle Family' for one somewhat further down the social scale.

Some aspects of it remind us of real families,but don't forget that TV is not real life and that the characters are really actors who act in a certain way to make us laugh.So of course it is not really a "typical British family".Rather they take some typical things that happen between parents and kids (and between the parents) and exaggerate them to make them funny.