Thanks for going ABCD (above & beyond the call of duty) on this question.

Stivell appears to have gathered a number of tunes from different Celtic regions for his Gaeltacht track so I would be very surprised if he threw in one of his own compositions and called it a Gaelic Waltz from Scotland.

As Phil said, it was 40 years ago. A lot of water under the bridge since then.

As I said earlier, this question was created out of curiosity and coincidence. The appearance at our session group of a piece of music called Stirling Waltz, which is the same music as the tune named Gaelic Waltz on Stivell's album, which you identified as a tune recorded by The Tannahill Weavers as The Galley of Lorne.

And then there is the chameleon nature of the tune. It appears to change time signature according to whichever musician is playing it. A tune is being acted on by the folk process and the transformations have been recorded and can be tracked and compared instead of simply evolving in isolation, as in pre-communications-technology times.

It's like a musicological/archaeological dig. Sorry. I'm getting a bit carried away by my own thoughts.

Sometimes I think of pre-comms-technology times and how musicians learned new tunes. They might have travelled to a dance or a ceilidh and heard a new tune, started playing it themselves, taken it back home and possibly mis-remembered the tune or even prefered to play it their own way, and then the tune evolves.

Like Darwin's studies on the evolution of animals. Or like the way that words from the Latin language have arrived into the English language either directly or through Roman, Italian or French or other linguistic influences, e.g the word "name" is related to the word "nominal". They arrived into English language through different languages, but originated in Latin.