Henry Ralph Mowbray Howard, 1911
(though the photograph is excellent, the RHS was problematic
and the date slightly underperforms, as is noticeable)
It's possible that the artist was James Philip Sydney Streatfeild
(5 Nov 1879 – 3 Jun 1915), though one would prefer to think not!
And of course the signature is inconsistent.
Maj Henry Ralph Mowbray Howard (18 Jun 1883 – 12 Aug 1950)