I have just acquired this interesting Japanese armband for an Allied POW medical officer and would like to find out more about that man, but have no idea where to search since he could have been from any of the above British Empire countries fighting the Japanese.

 

The only info I could get from the www.jref.com site is below: 

The three kanji above "Dr. Sturton" mean "Englishman".

Other kanji don't make much sense, and they are very poorly-written.  All the kanji written there, including "Englishman", are poorly-written, not just "other kanji".
It seems to me that the writer actually was not familiar with kanji or Japanese language.

 

That's a pretty broad search, and I'm not sure how you could narrow any results down without at least knowing where Dr. Sturton came from originally. That's a very nice piece you have, though!