At Pascoe's birthday party at the start of the episode you can see that he smokes cigars.
Dalziel lives at number 16.
Dalziel's car has the licence plate YD55BZX.
We discover in this episode that Pascoe's birthday is the 31st of October.
The ambulance at the start of the episode has 'Mid-Yorkshire' written on the side, which you can clearly see that it has been stuck on.
The book Pascoe picks out from the station library is called 'In group/out group - our need to belong by Ekta Walia.' This book does not exist and the author is the name of the show's Production Secretary.
The female pathologist taking over from Dr Mason is called Dr Griffin. This character is named after Assistant Production Accountant Claudine Griffin.
Houdini's Ghost is loosely based on the Dalziel and Pascoe book 'Good morning, midnight' by Reginald Hill, and is one of fewer episodes based on a book from the original series.
When Pomona closes the front door and Bowler leans his head against it on the other side, we can clearly see that it hasn't been shut properly. If he was to have leaned heavily on it he would have fallen into the house.
Sam: The second, B, Jax Ripley worked for the BBC didn't she.
Pascoe: C for Cyril.
Dalziel: I hope you're wrong Peter 'cause if you're not, the next victim's name begins with a D.
How did Dalziel assume that the next victim's name would begin with a D. Yes it follows alphabetically but with A and B they were not names but AA man and BBC. C could have stood for Councillor. So the D could also have stood for anything, not just names.
Dalziel still owns the car - Y94 YHM.
In the scene where Dalziel and Pascoe confront Jamie in the woods, Jamie points the gun at Dalziel. Pascoe then stands in front of Dalziel, shielding him. In between a shot of the body they have changed position and Pascoe is to the side and behind Dalziel.
In this episode Dalziel is driving a silver Rover, registration - Y947 YHM. Pascoe is driving a blue Audi, registration - Y202 BEP.
While Wield's angst over coming out and his relationship with the young interloper—who is even younger in the novel—adheres to Hill's original story, the rest of his half of the plot has been almost totally revamped for the screen. The story behind the Hubie family and the mysterious son, meanwhile, has almost no relationship to the novel whatsoever.
This episode is overall quite faithful to the book, and borrows some of the dialogue wholesale. However, the production team clearly wanted to make Peter Pascoe look good in this episode, and thus he gets to beat Supt. Backhouse to the punch (albeit just barely); this is not at all the case in the novel, in which the mild-mannered Backhouse out-detects a considerably chastened Pascoe on every front. Part of the backstory involving Davenant's relationship with Timothy Mansfield has vanished. Finally, for TV purposes, Pascoe's relationship with Ellie has been accelerated—they have not yet married in the novel—and Det. Sgt. Wield, who would not be introduced until A Pinch of Snuff (1978), is on the scene.