Assistant floor manager Ian McLean ordered "a selection" of branches for Cleese to select from to whack the car. He also suggested padding for the umbrella for Sybil to hit Basil and O'Reilly with. And he came up with the anagrams for the FT sign in the opening titles - the only true one is 'Flowery Twats'.
Ken Campbell was a last-minute replacement to play the character of Roger in The Anniversary (Series 2 Episode 5). Julian Holloway had been due to play the character but couldn't do it due to a strike. The strike was because a rigger had punched a BBC Executive in a corridor at TV Centre. The rigger had naturally been fired, but the unions decided that this was unfair dismissal and all went out.
The scenes with the rat in were pre-recorded, and these were the only studio based scenes which were. The reason for pre-recording them was in case anyone in the cast, crew or audience had a phobia.
The Series 2 episodes Communication Problems (Episode 1) and The Anniversary (Episode 5), are the only episodes to be given clear settings: a conversation between Basil and the Major reveals it to be St. George's Day (23rd April) when Mrs Richards checks in at the beginning of Episode 1, and then 17th April in Episode 5 when the Fawltys have their wedding anniversary.
Episode titles were never publicised at the time of broadcast, nor seen on screen, meaning that a number of episodes are known by other names in some places. The now 'official' titles were first given on mid-1980s VHS releases.
The Fawlty's car - a red Austin Maxi - has the numberplate OYF 747R.
John Cleese used one episode of Fawlty Towers to mock Private Eye editor Richard Ingrams, who made constantly references to his view that Monty Python's Flying Circus was not funny. In "The Kipper and the Corpse" Cleese showed a character called Mr. Ingrams blowing up a sex doll. Ingrams has described this joke as "pathetic" and that he would now be forever famous for being included in Fawlty Towers.
Source: The Museum of Curiosity, Series 6, Episode 3
In The Anniversary (Series 2 Episode 5), Basil is seen in the kitchen reading a newspaper with a headline relating to the show's real-life casting problem: "A PUNCH UP BLACKS OUT TV SHOW".