Hi Steve,
I hope you don't mind but a couple of interesting clues in trying to trace him down:
1. Next to Regiment it states: C in C BG
Engineers (at least I think that's what it says - I could be wrong)
2. There is a Henry Green from Cape Town born circa 1872 who was a Plumber who could be a possibility:
Full Marriage Cert:
The signatures are close but I still have my doubt:
Attestation Papers:
Marriage Cert:
The Henry Green above passed away in 1917 in Benoni:
Just a thought and good luck with the research.