In Season 2 Episode 5, Lionel and Jean are seen in bed together for the first time on the show, with Lionel on the left and Jean on the right. Lionel says, "We're on the wrong side", they switch, and both agree that it's better. But when Lionel moves in with Jean, Lionel is always on the left.
In Season 2 Episode 3 (1992), Lionel comments on Rocky's lifestyle, in that "the way he goes about life, he's only got two or three years at best." In Season 3 Episode 2 (1993), Lionel is on the phone with Rocky's doctor, Dr. Field, and tells Jean that "the old fool will be lucky if he lasts another year." In Season 3 Episode 10, Madge admits to knowing that "Rocky isn't supposed to have very much time." Nothing else was mentioned about Rocky's health. Ironically, in real life, Joan Sims (who played Rocky's wife, Madge) died in 2001. Also, she was not featured in Season 8, which aired in 2000, even though she was referenced.
Between Season 4 Episode 10 and Season 5 Episode 1, the layout of the interior of the house changes. Formerly, standing inside the living room, there was a wall outside the living room door, which the door opened from the right. Now, the door opens from the left, the wall is gone and you are able to see the front door of the house from the living room. In Season 9, the door opens from the right again.
In Season 4 Episode 5, Mike Barbosa gets to see Rocky's house, which as seen in Season 2 Episode 3, the front is 2/3 covered with moss. In Season 4 Episode 10, when filming begins for "Just Two People", the moss has been stripped away, presumably for the "filming". The moss is restored by the next episode (Season 5 Episode 1).
In Season 2 Episode 4, Lionel tells Jean that Alistair is looking after him like a baby because he is "a favor" - Alistair's father borrowed £500 from Lionel's father in 1947 to start a publishing firm. In Season 5 Episode 3, Alistair approaches Lionel with a book for Lionel to adapt in to play or film. Alistair tells Lionel he "snapped up the rights" per his publishing company. Later in the episode, Lionel finds out that Alistair's father bought the rights in 1932. The publishing firm wasn't created until 1947.
During the entire 1995 series, the copyright date is displayed as MCMXV (which is 1915). It should have said MCMXCV.
The opening sequence shows Lionel writing the missing letter from Korea. It is dated January 14th 1953. Yet throughout the series, they talk about Lionel being in London in August 1954, before he goes to Korea. In addition, the Korean War finished in 1953.
Also in Season 4 Episode 10, Madge is seen holding up a sign in the window that says, "Ban Blood Sports". The room she is in does not fit with the layout of the house. When Mike Barbosa enters the house, he enters the room from Madge's right. The sign was held to the left of the house entrance. Besides, the fact is the windows are of two different styles between where the living room is situated from the outside, and the view from the inside.
The opening sequence shows Lionel writing the missing letter from Korea. It is dated January 14th 1953. Yet throughout the series, they talk about Lionel being in London in August 1954, before he goes to Korea.
In Season 3 Episode 2, Lionel is telling Rocky a joke about a parrot with no feet. ("So the parrot said, 'No, I didn't see a thing. I got so excited I fell off my perch.'") Rocky replies, "I understand the joke, I just don't think it's funny. In Season 9 Episode 3, Rocky tells the same joke to Mrs. Bale, laughs, and admits, "It's a very good joke, that!" (Note: "Season 5 Episode 6 has Lionel telling the joke to Steven, who doesn't get it.)
In Season 2 Episode 3, the first time Rocky is seen speaking to Mrs. Bale, he calls her Mrs. Bales.