Without wanting to get into a debate on the meaning of 'traditional', I'm puzzled by your assertion that Farewell to Tarwathie was written in the 60s.

I assume you mean the 1960s? If you read through this thread you will see that the words were written in the 1850s by George Scroggie, and published in 1857, so you're a little bit out.

The tune is more of a problem. It was likely an existing traditional tune was used by Bert Lloyd to set the words to, but which one? Green Bushes has been mentioned as a contender, although the versions I have (Baring-Gould, Sharp (2) and some others) are quite different.

Still, singers have been pairing pre-existing lyrics and tunes since ... well, they've/we've been doing it for a long time. That just shows that the tradition is alive and evolving, and that, for me, makes it healthy.