Actor Allusion: In a Comic Relief episode Uncle Albert mentions how nice it would be to walk through a door into the 1940s, which Rodney dismisses as stupid. Raquel then goes to bed and Del says "Goodnight Sweetheart.". Del then remarks that he is not a chief inspector.
This was also done the other way around—in Goodnight Sweetheart Gary (played by Nicholas Lyndhurst) is about to lean back and fall through an open bar door like Del Boy famously did, but notices in time and gives an Aside Glance wink to the audience—accompanied by uproarious laughter that must seem inexplicable and random to anyone unfamiliar with the Only Fools scene in question.
Casting Gag: Douglas Hodge, the then-husband of Tessa Peake-Jones, who plays Raquel, was cast as the grown-up Damien in Rodney's dream in "Heroes and Villains".
Both Grandad and Uncle Albert when their respective actors passed away.
Averted with Mike the Barman. Before his death from cancer, Kenneth McDonald didn't want his character to be killed off, so in the 2000s specials, his absence is explained as being imprisoned for embezzlement, having lost everything in one of Del's schemes.
Dawson Casting: Although Cassandra was supposed to be five years younger than Rodney, in real life Gwyneth Strong is actually two years older than Nicholas Lyndhurst.
Doubling for London: The outdoor scenes were filmed in Bristol as the producers could not afford the insurance to film in Peckham.
Follow the Leader: John Sullivan convinced the BBC to go ahead with the series based on the success of Minder, another comedy series about a London wheeler-dealer.
Due to music licensing laws, the BBC has replaced the original soundtrack on many episodes, and in some cases simply cut out scenes where the offending music is being played. John Sullivan's family were not happy with the results. The law on music licensing has since changed, meaning the original unedited episodes could now be released, but the BBC is yet to do this.
The same applies to the original version of "A Royal Flush," which is unavailable on any home video format (the VHS release had about a minute of footage removed, and the DVD release removed nearly ten minutes of footage and added a laugh track). However, the original cut still appears from time to time on UKTV Gold and other such channels, so it's not too hard to find decent quality versions of it.
In a straight version, several mini-episodes such as Christmas Trees, Licensed to Drill and the Comic Relief Special have never been released on VHS or DVDs.
Old Shame: Nearly everyone involved with the series regards "A Royal Flush" to have been a huge misfire, to the point where John Sullivan admitted in an interview on the day that the series' Grand Finale was broadcast that he wished he had never written it.
Only Barely Renewed: Due to poor viewing figures, the series was almost cancelled after two series. However, it was repeated in a low key time slot and achieved respectable ratings, which convinced BBC producers to commission another series. The show went from strength to strength thereafter and ironically was continually revived during the 1990s and 2000s owing to its status as a ratings winner.
Or what could have not been. Due to disappointing viewing figures for the first two series, the show was nearly cancelled altogether. However, the first and second series were repeated in a low key time slot in June 1983 and achieved respectable ratings, which convinced BBC producers to commission a third series. The show went from strength to strength thereafter.
Jim Broadbent was John Sullivan's original choice for the role of Del. While Broadbent turned down the role, he did later make three guest appearances in the show as DCI Roy Slater. Had Broadbent been cast, not only would we have had a completely different Del Boy, but he has stated in interviews that he would only have made one or two series before moving on, and thus the show would never have become the major hit it did later.
Enn Reitel, Robin Nedwell, and Billy Murray were also considered possible candidates for the role of Del, before it went to David Jason. Roger Lloyd-Pack was also considered, before being cast as Trigger.
John Sullivan intended for Chas & Dave to sing the show's theme song due to the success from their "Rockney" style of music (a mixture of rock 'n roll and cockney). However, they were unavailable having just recorded their hit single "Ain't No Pleasing You", so Sullivan sang the song himself after being persuaded by Ray Butt to do so.
In 1986, David Jason told John Sullivan that he wanted to leave the show and further his career elsewhere, so the fifth series finale "Who Wants to Be a Millionaire" was written as the final OFAH episode, and would have seen Del leaving England with his friend Jumbo Mills to run a car business in Australia. A spin-off entitled Hot-Rod was planned, which would've been all about Rodney running Trotters Independent Traders with Mickey Pearce. However, Jason changed his mind and decided to stay on, and Sullivan rewrote the ending to show Del rejecting Jumbo's offer.
The poor reception of 1986's Christmas special, "A Royal Flush" caused outgoing producer-director Ray Butt to tell John Sullivan that the series had run out of steam, and to let it end with the following year's Christmas special, "The Frog's Legacy." Sullivan did consider doing this, but ultimately decided against it after "The Frog's Legacy" got a much better reception, though he did give the series a major retool afterwards.
John Sullivan originally wanted to make Cassandra a girlfriend of Trigger, Denzil or an admirer of Boycie, but decided that like he planned to do with Del, Rodney needed a long term relationship.
An American remake of the show was once said to be in the works, but never surfaced.
In the first chapter of the early 2000s Christmas trilogy, "If They Could See Us Now" (2001), The BBC wanted to get the rights from ITV to use the actual Who Wants to Be a Millionaire? gameshow with a special guest appearance from Chris Tarrant, but ITV refused because a plot point was that Del gave a correct answer and the quizmaster said it was wrong due to an error. They ended up with a blatant expy called Goldrush, hosted by Jonathan Ross.
Anthony Hopkins, a big Only Fools and Horses fan, was keen to appear in the series. John Sullivan even wrote the part of Danny Driscoll for him, but filming clashed with The Silence of the Lambs and he therefore had to pull out.
Write What You Know: Most of the show's storylines were based on events in the life of creator John Sullivan and/or members of his family. Similarly, Del Boy's characterization was essentially a combination of Sullivan's father and the show's initial producer-director, Ray Butt (who Sullivan had previously worked with on Citizen Smith).
You Look Familiar: Jumbo Mills, Del's old friend and business partner, is played by Nick Stringer, who also appeared in the Series 1 episode "Go West Young Man" as an Australian to whom Del sells a car with faulty brakes.