I don't have the book, it's a scan held at Internet Archive: Digital Library of Free Wayback Machine.

There's nothing in the nominal roll on p.267 that suggests he was wounded and he's not mentioned anywhere else according to the search engine on that site. The roll is a bit confusing but if one goes back to the first page it is stated to be a list of all those who served in S.A. and the blanks after names thus indicate no record rather than a "ditto" effect.

As far as I can see Stenson came through unscathed. He must have been lucky or smart enough to avoid dirty water or other contaminations that led to the "enteric fever" which killed about as many as combat.

Around this time the Japaneseicon were getting very interested in those famous (Royal) Doulton ceramic water filters which the WO seems to have overlooked - and which are still in use today of course. Gen. Ishi of Unit 731 infamy got his start in this field IIRC. The Japanese eventually found ways to pump the water through the filter media rather than just using gravity feed which increased the output enough to make it useful in the field.

But getting back to Stenson, I found no clear trace of him after the war. If you can access records of the 18th through the museum of The Royal Hussars or whatever the successor regiment is, you might find out what became of him. The fact that such an object was still in the UKicon suggests he didn't emigrate, but it's also the kind of thing that was often "sent home" to relations when an emigrant died somewhere abroad.

(Many keyboards have a "print screen" key which temporarily saves a "screen shot", which can then be pasted directly into MS Paint or another image manipulation program for further editing and saving under whatever name one chooses.)