@panzade,
Sydney isn't Australia. And your mother's taste may have been influenced by her beau. Seriously - you look at the charts for the fifties (admittedly they don't start until 1956) the only countryish artists are the Everly Brothers and Johnny Cash, a little Marty Robbins, Frankie Laine and Guy Mitchell. No Hank Williams, Bob Wills, Ernest Tubb. Basically stuff that had crossover appeal.
We didn't have genre radio stations or massive regional differences in taste like the US. Even our home bred country stars were rare visitors to the charts.
My dad was a country boy, and my mother was a German refugee. And dirt poor. I guess what I'm saying is I had no exposure to it until well after the fact and despite what your mom's experience it wasn't mainstream anything like the US.
Edit - just realised I read what said wrong - it may have been big in 44/45 but the taste for it faded after demob apparently.