Definitely SWANSTON.
Captain H O Swanston gets several mentions in the newspapers of the day, Captain H O Swanstone none:
York Herald 14 December 1899:
The next indicates what happened next:
The Globe 22 March 1904:
Find My Past has this transcription record:
First name(s) Hugh Owen
Last name Swanston
Year 1899-1902
Rank Major
Regiment 1 Battalion The York And Lancaster Regiment
Rolls WO100/341 page 162
Literary references DOVTwice Captured: Earl of Rosslyn 185
Notes KSA Clasps: SA01,SA02
Country Great Britain
Record set Anglo-Boer War Records 1899-1902
Knowing his full name allows one to find further evidence - his birth certificate & probate:
Also found him on a ship in 1919 returning from Africa:
I think you may now know more than you ever wanted to know about Hugh Owen Swanston (1871-1933). Don't ask me what "Literary references DOVTwice Captured: Earl of Rosslyn 185" means.