In the final episode of The Good Life, starring, among others, Penelope Keith, Sir congratulates Jerry on being made the head of the company. In his congratulating him, he says something along the lines of "Next thing you know you'll be off to the Manor Born". Now, a little while after The Good Life finished, a new series starring Penelope Keith began, called To The Manor Born. Do we know whether this was an intentional reference to the new show? Or, perhaps, this was inspiration for the name of the new show.
The idiom is "To the manner born". It is used to describe someone who behaves according to their upbringing rather than the expected behaviour of their situation.
The title of the series To The Manor Born is a deliberate pun on the idiom. The Penelope Keith character, Audrey fforbes-Hamilton, behaves as though she still owns the manor.
The reference in The Good Life tells Jerry and Margo Leadbetter that they may now behave as to the manner born. A compliment, essentially that Jerry was born to reach the position he has now attained.
Was one a reference to the other? Probably not, the creators and writers of the two series are not the same. The final episode of The Good Life, like so many final episodes of long-running series, was a tying up of loose ends.
Actually, since the character from The Good Life states "You'll be off to the Manor Born", I can see how this can be interpreted as "The Manor Born" being a physical place, such as another sitcom.
The idea for the sitcom To the Manor Born was actually conceived by Peter Spence in the early 1970's after having a conversation with a comedian.
Peter Spence first thought of the idea behind To the Manor Born in the early 1970s when he was working for BBC Radio as a gag writer. One of the programmes that Spence wrote for featured a Cockney comedian, who had recently bought a manor house in an English country village. When holding a housewarming party, the comedian invited the previous occupant, a widow who could not afford to keep the house up and had moved to a smaller house in the village. The comedian's account of the lady, and the conversation he had with her, Spence later described as a "perfect description" of Audrey.
A few years later, following the success of The Good Life, Spence was asked by BBC Radio to come up with an idea for a programme to feature Keith.Thinking of Keith's character in The Good Life, Spence had the idea of an upper-class version of Margo Leadbetter and, from the account from the comedian, came up with Audrey fforbes-Hamilton. Instead of a Cockney comedian as the new owner of the manor, Spence decided on an American who sees the manor while in England looking for his roots. The American later discovers he is descended from the fforbes-Hamiltons.
Although Spence thought of Keith's character from The Good Life while coming up with an idea for BBC Radio, (which later became the sitcom, To the Manor Born) there is no evidence that suggests that the phrase spoken on the final episode of The Good Life was an inspiration of To the Manor Born.
An interesting fact:
The Good Life aired for four series and two specials from 4 April 1975 to 10 June 1978. The final one-off episode, "When I'm Sixty-Five", was a Royal Command Performance in front of The Queen, The Duke of Edinburgh and senior BBC management. The cast and crew were presented to The Queen and Prince Philip after the recording.
Perhaps the phrase "To the Manor Born" was in the final script due to the presence of royalty? An interesting fact to ponder.