I hesitate to post yet another set of words as we already have so many in this thread, but it is clear from George's quoting of the lyric from the Silly Wizard lyrics site that this particular English translation is the work of Thomas Pattison; it was published in Songs of the North (A.C. MacLeod and Harold Boulton, 1895).  The transcription given differs in a few places, and not having the record in question, I can't tell whether this is the result of mis-hearings by the transcriber or by the band.  Here it is, then, for what it's worth.

THE BOATMAN (FEAR A BHATA)

(Translation by Thomas Pattison)

How often haunting the highest hilltop,
I scan the ocean thy sail to see;
Wilt come tonight, love? wilt come tomorrow?
Wilt ever come, love, to comfort me?

Fhir a bhata, no horo eile,
Fhir a bhata, no horo eile,
Fhir a bhata, no horo eile,
O fare ye well, love, where'er ye be.

They call thee fickle, they call thee false one,
And seek to change me, but all in vain;
No, thou'rt art my dream yet throughout the dark night,
And every morn yet I watch the main.

There's not a hamlet -too well I know it-
Where you go wandering or stay awhile,
But all its old folk you win with talking,
And charm its maidens with song and smile.

Dost thou remember the promise made me,
The tartan plaidie, the silken gown,
The ring of gold with thy hair and portrait?
That gown and ring I will never own.

The differences are only slight, but make better sense; since this is the work of a known writer (albeit probably now out of copyright), I think it important to give the lyric as he intended it.  Whether the band credit him on their record I do not know.