Porter and Bald go to Sierra Leone amidst the backdrop of the SL civil war that racked the country from 1991 until 2002. They are asked to protect a former SAS CO, the one who had wrecked Porter's career. In a sense, this book is somewhat dated in 2020. However, having seen the updated series, first with John Porter (played by Richard Armitage (The Hobbit trilogy, Ocean's 8) being a solo act (Bald was written out), and then with Philip Winchester and Sullivan Stapleton as Stonebridge and Scott, respectively, you really do feel the essence and action in this book.
Chris Ryan and the TV series often use "Crooked Civil Service Bureaucrat" trope - the guy who end up in middle or senior government management through the Old Boys Network (Cambridge/Oxford for British authors, Harvard/Yale for American authors) or has blackmailed someone to get where they are, or if it is a ruthless female, sex. Or, they demonstrate all too well the Peter Principle - you are promoted until proven incompetent - usually a military officer who got promoted just to get out of the way of those who actually can do the work.
Having read many of such books, you might roll your eyes, but you are still hooked because 1) the author hooks you in with other details, 2) you know such people and want to see their comeuppance, if only in a book , 3) you don't care about such tropes because you don't believe in "originality" as a cardinal virtue, or 4) all the above.
BTW, there was a sub-thread with "tourists" who got caught in the hotel siege. After 3 pages (and the hotel siege was half the book), I figured out who they really were, but I won't say much more.