As a devotee of Agatha Christie's Poirot mysteries, I am also a huge fan of David Suchet. He has made the character of Poirot his alter-ego while still being faithful to Christie's creation. My family and I watch these mysteries over and over again.
This production of "Taken at the Flood" is the exception. This no fault of Suchet's, but rather the screen writers who inexplicably thought it necessary to darken the cast and muddy the plot. Some story elements and important characters were changed for unfathomable reasons. The most outstanding example is the character of David, who was recast as a violent sociopath, rather than a ne'er-do-well opportunist, leaving viewers to wonder what could make any woman, much less the independent and lovely Lynn, give him the time of day, never mind her heart. When the murderer is revealed, the character is so far removed from the Christie's genre as to be unrecognizable. The writers resort to outright creepiness for effect, rather than on Poirot's masterful unwinding of the plot as originally written, as most Christie enthusiasts expect and enjoy.
The circumstances of the seminal explosion, formerly part of the London Blitz, was changed to accomodate a criminal descent into madness. Perhaps this mirrors the journey of the screen writers who have taken a coherent and brilliant plot and changed it to one that makes this Christie enthusiast cringe.
All of which begs the question: Why rewrite an excellent mystery?