Read this after being caught up on the addictive DCI Craig Gillard series. While that series excels in the detective-work-and-personal-life story arc, Heartbreaker falls in a different genre. While there are detectives and lawyers in the cast later in the book, the main characters are journalists - plus some terrorists.
Compared to the DCI Gillard series, this book is much more cinematic, to the point of working in multiple countdown timer type scenes ("spoiler:" the day is saved, with seconds to spare!) This is where it veers into action movie script territory, quite different from DCI Gillard. Also, the Really Bad Guys sure are ... Really Bad.
In fairness, Louth does build a compelling back story for Wyrecliffe, with his buried secrets gradually unfolding as the story develops. DCI Gillard's past is developed more gradually over many titles in the series, and isn't a central plot point in the crimes he is solving, instead forming a parallel thread running through the series to add dimensionality and interiority.
In Heartbreaker, cellphone coverage issues are recurring plot devices, and there's a troubling amount of "I need to see you in person, can't talk about this on the phone" -- when the reader knows the caller is the only one with vital information, leaving us REALLY wishing they would have just blurted it out.
Good reflections on who counts as "believable" when telling a pretty hard-to-believe story.
Also very interesting imagining of life within a jihadist group, and how a British Muslim might be drawn into one.