The show's title comes from the stereotypical average size of a nuclear family in the UK at the time the first series was written.

Lead actor Gary Olsen died in 2000, which effectively ruled out any possibility of the show returning for further series.

The role of Jenny Porter was recast partway through the run, played by Clare Woodgate in series 1 and 2, then by Clare Buckfield from series 3 onward.

Several supporting roles were also recast over the years, including Tina Porter (played by Patricia Brake in series 1, then Sandra Dickinson from series 2) and Declan (played by Mitchell Ray in series 7 and Alex Kew in series 8).

Although the series was produced over eight years, the in-universe timeline appears much shorter, since Jenny Porter is stated to be 14 in series one but only just starting university at 18 in the final series.

Writer Andrew Marshall penned nearly every episode himself, with only three episodes in series seven written by other writers: Paul Alexander, Simon Braithwaite and Paul Smith.

Traditionally, the Christmas episodes featured the cast collectively performing a musical number, such as carols or original theme songs.

DVD releases stalled after the first three series were issued by Eureka Video in 2005 and 2008, as the company reported poor sales and BBC Worldwide's 2Entertain cited high music and imagery clearance costs as the main barrier to releasing the remaining series.

A Dutch remake titled Kees & Co, starring Simone Kleinsma, debuted in 1997 and ran for eight series until 2006, with the first five series adapted directly from the original English scripts before switching to original storylines.

In 2004, the series was ranked #44 in the BBC's television poll Britain's Best Sitcom.