Jones walks past a red Jaguar series one E Type as a young man says "what's your problem?" As Jones replies he passes in front of the car which has changed into a series two E Type with open headlights. Also the people standing round the Jaguar have completely changed.
Peter Fossett explains to Dave Doggy Day how to start a vintage Alvis. One of his instructions is to advance the ignition when starting; this is not true. The ignition timing should be retarded when starting, then advanced when the engine is running. Dave Doggy Day later repeats the incorrect instruction.
When DS Jones introduces DCI John Barnaby to Harriet Wingate, before she walks away she says, "Nice to meet you, Tom!"
In the race commentary at the beginning of Death In The Slow Lane the commentator refers to Luffiield Corner at Silverstone. At that time the race was supposed to be run Silverstone didn't have a Luffield Corner which was older added with track modifications in the 1990s.
In Barnaby's personnel record, his Midsomer address has a postcode starting with CA6. That postcode is for addresses in Carlisle, nowhere near the Oxfordshire/Buckinghamshire area where Midsomer is supposed to be.
Sgt Jones says that when Palmer's remains were found in his racing car under a sheet and under some bales of straw in a barn, it was assumed that the death was suicide since his gun was next to him, without at anytime wondering how after committing suicide the dead man managed to hide himself under a sheet and several bales.
Not to mention, the bales of hay Palmer was under would not have survived 45 years in the barn; they would have rotted away long before then.