Dirty Story

I feel this book is really is 2 parts. Part 1, a very slow build up, setting the scene for Arthur getting into the story. Passport Trouble.

He does not so much as convince them of his soldiering experience, he just never corrects a series of misunderstandings and assumptions.

Part 2 the story. With a punchline and a set up for the next book.

I think the book could really have been a short story or novella - Part 2- he ends up as a mercenary, a colonial officer training local soldiers, then an incursion.
There is a good part that illustrates the fact that they are professional soldiers for hire, when they meet the opposing force and one of them is an old friend/colleague - he's not disarmed, he offers some information to minimise casualties and they discuss if the incursion might well be reversed in the evening.
It's a profession, the europeans intend to get paid and live for the next assignment.
The natives are not treated in quite the same civilised way.