To tell you the truth it is one of those programmes that normally takes you up to the catching of the villain. Not like "Law And Order UK" where you first see the catching then the court case and sentencing too. So whether hanging was still around or not is possibly not that relevant. A passage of time means there can be ongoing stories as well as each individual criminal case. For instance Bacchus left and divorced his wife then later had an affair with another officer's wife which Gently put a stop too. And now gently has the onset of multiple sclerosis to deal with!