At the end of the book the author quotes some military books from which he built up this part of the action and another anomaly is his mention of the Lewes bomb. To explain, Lt Jock Lewes was a member of the L.R.D.G in the western desert in 1942 and devised the explosive device which bore his name.
https://www.amazon.com/Reckoning-Novel-John-Grisham/dp/0385544154