Hi!
Sorry for the late response, I somehow missed your post!
I don't have anything that I'm sure about on Thomas McKenzie between the 1901 census and his marriage in 1919. I have his passenger record for the journey to Melbourne, Australia on the Largs Bay on 10th May 1927, with Elizabeth. I am sure that it is his death record from Australia. On the record it states:
He was 85 years old at his death in 1970.
He was born in Ross, Scotland, to John McKenzie, Shoemaker, and Mary McKenzie(nee Munro).
He married Elizabeth Hall at the age of 28 in Glasgow, Scotland.
It also states that he was a widower at the time of his death, had no children, and had lived for 45 years in Victoria, Australia.
Have you found him in the 1911 Census?
Did you find his Military records?
Belinda