Mr Powter was the 1918 Durban champion and won the title only once.
There is a short mention of him on page 127 of Len Reitstein's book
"A History of Chess in South Africa", where the final moves of
Archer vs Powter from the 1926 Durban championship are given (Archer won).
In his comments, Reitstein says that Powter and Archer tied for 2nd place on 6 out of 9, just half a point behind McCord, who defeated Archer in the penultimate round of the 1926 championship.
Incidentally, there is a gravestone in the Umkomaas main cemetery for a Philip Powter (1851-1929) who could be our man, but that needs confirmation!
I have not yet found any complete games by Mr Powter.