Hey, It's That Guy!: Jim Broadbent plays Slater. Less significantly, Lennox Gilbey from "The Longest Night" was played by Vas Blackwood, aka Rory Breaker in Lock, Stock & Two Smoking Barrels. Eagle-eyed viewers might also spot David Thewlis as one of the members of the band in the fourth season episode "It's Only Rock and Roll".
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.
Jim Broadbent was John Sullivan's original choice for the role of Del. While failing to get the role, he did still appear within the show as DCI Slater, who made three appearances - all highly memorable.
Enn Reitel, Robin Nedwell, and Billy Murray were also considered possible candidates for the role of Del, before it went to David Jason.
The fifth season finale "Who Wants to Be a Millionaire" was originally written to become the final OFAH episode with Del leaving England with his friend Jumbo Mills to run a car business in Australia, thus launching a planned spin-off series called Hot-Rod, which would've been all about Rodney running Trotters Independent Traders with Mickey Pearce. However, David Jason changed his mind and decided to stay on, and Sullivan had to rewrite the ending so that Del turns down Jumbo's offer.
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.