The Perth & Perthshire Branch Newsletter "The Highland Gateway" for January 2011 has the following text:

"From locally here in Perth, Scotland, the links spread internationally to Perth, Western Australia where the RSCDS Branch was asked to contribute a reel and a strathspey in honour of the Perth 800 anniversary. The dances “The Swan and the Tay” (which represents the two city rivers) and “Perth meets Perth” (representing dancers crossing the world to join together in the dance) were submitted. Appropriately their tunes “Mo Rutherford’s compliments to Frank Thomson” and Jim Johnston’s “The Carse of Gowrie” were arranged by Mo Rutherford, former RCDS Musical Director, and of course one of Perth‘s best known musicians."

So this dance comes from Perth (Australia), but was published in Scotland in the RSCDS booklet "Perth 800" in 2010.