Actually I might have got my horses mixed up which is not surprising when a trotter is written about on the galloping forum.
Durban Chief was bred amd raced by W. E. Craddock (Bill) of Westport. Bill was the Mayor of Westport, President of the Westport Trotting Cup and the longest serving councillor of the NZ Rugby Union. Bill often stayed at my childhood home when coming back from overseas Rugby Trips. One in particular was he returned from managing the All Blacks on tour in South Africa. He did have part ownership of Durban Chief.
http://www.hof.co.nz/Timeline.asp?Case=6&ItemId=45&AlphaId=3&CategoryId=3
I'm now not sure what the famous horse I saw herding cattle on the road near Hari Hari was. I thought it might have been a famous West Coast owned thoroughbred named Dalray. He won the 1952 Melbourne Cup. He also won his maiden race at Westport. But it can't have been him because he went to stud in Australia unless he retired back in NZ.
https://westcoast.recollect.co.nz/nodes/view/23149
So the horse with a name that started with D escapes me at the moment.