I confess I enjoy these generally ridiculous Buchan novels. He's super colonialist, with all the awful things that implies, but in an innocent, too-dumb-to-know-it kind of way. Rugged individualists travel to remote locations (remote to English people) to "make their pile" saying stuff like "I let fly and gave him what for!" and other goofy things.
It's basically if you took Orwell's novels on colonialism and removed all nuance, irony, and self-awareness of one's advantages and consideration for anyone but yourself (and the British empire). I'd like to think Buchan was in on the joke, or that it was a joke, but I've never seen evidence that's the case (haven't looked either, though).
His books are "fun" to read more as a relic of that time and the kind of books it produced. Though I confess I love the way he refers to obscure events of bygone eras, and personalities of that time, as if everyone knew about them and couldn't possibly NOT know all about them. I feel like I should get a trophy, or maybe an invitation to a men's club with leather recliners and servants and brandy and cigars, when I do understand a reference. But I'd politely decline the invitation, of course.
LOL, I wrote all that before I read John MacNab and it's pretty spot-on. A bunch of bored rich people conjure up a wild (for landed gentry) plan to escape their boredom, without a thought to all the working class stiffs who have to work all day to play at their silly game. Everyone goes home a winner, even the fish kid, though he gets kicked out of the car to watch a rich guy's dog at one point. Alas poor Fish Benji.
Anyway, these novels are a relic of a bygone age, though the current age is even worse for the workaday saps sucked into the orbit of knuckleheads bored with all their inherited wealth and power. Oh well. Not one of Buchan's best, certainly not as fun as the globe-trotting novels he's better known for.
It's also worth noting (probably higher up than this, sorry) that Buchan is super racist in that 1880s kind of way. He drops an N-bomb with casual aplomb like the worst of his sort, and one character literally gets out of trouble by pointing out that he's white. The other guy is like "Oh, OK, you're cool then." Ugh.