This is a different Inspector Alleyn mystery, in that it is his wife, Troy, who is centre-stage for much of the story. Troy takes to the canal in a pleasure-craft for a bit of peaceful painting - only to find that one of her fellow-passengers goes overboard in the middle of the night. There are mysteries about most of Troy's erstwhile companions, who are a motley group of customers. She pops off to report her suspicions when the boat stops for the night at various towns along the canal. The plodding policemen she encounters are probably the weakest part of the story. Once Alleyn himself becomes involved, the action hots up and the denouement is well-handled and unexpected (to me anyway!).
Both writer and narrator step outside their familiar backgrounds to differing effects. Bentinck leaves behind his normal bucolic beat and clearly relishes the freedom to produce a range of accents and vocal flourishes all of which add to the fun. It is his contribution that makes me give it four stars rather than three. Not that there is anything wrong with the story. The plot is complete tosh of course and I can't be the only reader/listener who finds Alleyne deadly dull as a character. However the real weakness is the passing of time. Novelist and protagonist now find themselves in the modern era (i.e. the 1970s) and neither are entirely comfortable in a world where everyone lives in a 'pad' and wears flares. I'm not sure that Marsh's version of heroin addiction is totally accurate either. A pleasant enough listen for a long car journey though.