What is the author's style in A Town Like Alice by Nevil Shute?

A Town Like Alice is told from the point of view of Noel Strachan, an aging senior partner in a London law firm. At the end of the novel, Strachan explains how he has devoted the last three years of declining health to going over precious correspondence with his client, the protagonist Jean Paget, and writing up her amazing story. In the early chapters, he shows her telling him the details, and each chapter ends with them coming back to the present for a brief reflection.

Strachan at times speaks in the first person, talking about his interactions with Paget, and sometimes reproduces conversations so intimate and detailed that it is difficult to imagine any letter or conversation that could have conveyed them to him. Much of the time, Strachan recedes into the background, allowing the story line - particularly in Australia - to move forward on its own, but he returns for the final first-person chapter, in order to contemplate the meaning of all that has transpired.

The core of Paget's story is based on a real-life incident, as Nevil Shute explains in the author's note that follows the text: "After the conquest of Malaya in 1942 the Japanese invaded Sumatra and quickly took the island. A party of about eighty Dutch women and children were collected in the vicinity of Padang. The local Japanese commander was reluctant to assume the responsibility for these women and, to solve his problem, marched them out of his area. So began a trek all around Sumatra that lasted for two and a half years. At the end of this vast journey less than thirty of them were still alive."