It is actually Lionel Rowlette who was a Captain when the first photo was taken in 1917, I believe, but when he retired from the army post WW2 he was a full Colonel. He also received the D.S.O. and my understanding is that he was "mentioned in dispatches" but I don't know if this relates to WW1 or WW2.
His son was also an officer in the Britisharmy, serving during WW2 and post war but only making the rank of Lieutenant Colonel. The son served in the Enniskillen Fusiliers and served at an army base in Northern Ireland for some of the 1950's.
As an aside I do have the son's metal uniform trunk in a fairly inaccessible part of my attic.