This Christmas special is dedicated to the memory of Margaret John (1926-2011), who played the neighbour Doris. The rest of the characters also raise a toast in her honour during the Christmas Eve scene.
Glenda is mentioned as being the children's babysitter on Christmas Eve. The real-life owner of the house used as Gwen's house in the series is named Glenda.
This Christmas special become the most watched TV comedy for 17 years in the UK with a total of 17.1 million watching the episode live and on catch-up.
This episode continues the characters lives 10 years on from the end of series 3, both in real-time, and within the story universe, as character "Neil the Baby" is now age 11, according to character dialogue.
Bryn still has his "My niece went to Greece and all I got was this lousy t-shirt" t-shirt, from over ten years ago.