There are only 10 Yeowardslisted on the white pages for the whole of Australia. You can see these on www.whitepages.com.au
I also checked on the Census pages for Australia on Ancestry.com but the only name that came up was "Ewart". Could this be an incorrect spelling based on pronunciation? If so there is an Eric John Ewart living in Dalby, Queensland, Australia up to 1954.

Good Luck.