There was a character in the first episode called Bracewell, played by John Ringham, who was intended to be another regular character in the series. However, the writers felt that they had too many characters and that he was too similar to Godfrey so axed him from the show. He was only mentioned again once in the following episode.
Source: The Complete A-Z of Dad's Army by Richard Webber, with Jerry Perry and David Croft. Page 34.
The theme song "Who Do You Think You Are Kidding Mr. Hitler?" was the last song sung by Bud Flanagan before he died.
Also, the original theme song was longer. On one of the DVDs you will find an Easter Egg with this extended version.
Dad's Army was one of the first TV shows to make the move from black and white to colour.
On a related note, Lavender also claims to be the first actor to play a character killed by a colour television saying, "I was also the first actor to be killed by a colour TV set on colour TV in Z Cars when a robbery went wrong and the TV set was dropped on me from a great height by Nicholas Jones".
The controller of BBC1 (between 1967 and 1973), Sir Paul Fox, played an instrumental part in the creation of the show's trademark closing title sequence. Both Jimmy Perry and David Croft originally envisaged the characters marching in front of a background of genuine war footage, including Nuremberg rallies. However, Fox felt this too harsh and serious, and overruled them. To this day, both sides stand by their choices.
In the final episode, Never Too Old, Mrs. Fox's Christian name is given as Mildred; however in earlier episodes she is named as Marcia.
In his appearances to the end of Series 5, Harold Bennett's character name is given as Mr. Blewitt. From Series 6 onwards it is spelled Bluett.
Whilst a precise location for Walmington-on-Sea is never given, it is known that the fictional town is set on the south coast, and in the 1971 film version of the series, the local police station is signposted as part of the Kent Constabulary.
The nearby (and equally fictional) town of Eastgate was named after Eastbourne in East Sussex.