When LeVanu is being interviewed on the radio, the frequency of the station as advertised on posters in the studio (86.6 MHz) is not the frequency that Jones tunes to (93.5 MHz) when he and Barnaby listen in the car. Also, 86.6 MHz is outside the range 87.5-108.0 MHz that is used by FM radio. Moreover, the posters call it "Causton FM", whereas the announcer calls it "Radio Causton". (A similar thing happens to "Radio Midsomer" in the Season 20 episode "Till Death Do Us Part".)