Malcolm noted (on the other thread) "Lady Mary Ann" by Robert Burns in DT. It's from 'The Scots Musical Museum', #377 (with 'straught' mispelled).
C. K. Sharpe gave a 'Lang a-growing' text only slightly differently from that in 'A North Countrie Garland' in 'Additional Illustrations to The Scots Musical Museum,', #377, but with a bit more Scots vernacular, and chorus given in full on several verses, and said his text was from a manuscript.
He repeats a little of the earlier note on Craigston (not Craigstoun) and Elizabeth Innes, including the reference to Spalding's History, vol. I, p. 36. He said that the ballad first appeared in Maidment's 'A North Countrie Garland', 1824, but made no mention of his connection with that text. He said Burns noted the song and tune (in SMM) from a lady in 1787, during his tour in the North of Scotland.
Earlier, Stenhouse in 'Illustrations to the Scots Musical Museum', #377, said Burns modeled his song on a fragment of an ancient ballad entitled "Graigston's Growing" still preserved in a manuscript collection of Ancient Scottish Ballads, in the possession of the Rev. Robert Scott, minister of the parish of Glenbuchet. [The forthcoming Glenbuchat MS]. I suspect the text in 'Additional Illustrations' is that from the Glenbuckat MS. This would mean that C. K. Sharpe didn't collect it, and I understand that there are no tunes for ballads in the Glenbucket collection.
Undoubtably Stenhouse was correct and Sharpe was wrong on the source of Burns' song. Burns' source was probably the fragment in David Herd's MSS (which, it has been noted elsewhere, Burns had seen) c 1776 [p. 145 of Hans Hecht's 'Songs from David Herd's Manuscripts', 1904] where the fragment is the following:
My love is long a-growing
She looked o'er the castle-wa',
She saw three lords play at the ba':
"O the youngest is the flower of a',
But my love is lang o' growing.
"O father, gin ye think it fit,
We'll set him to the college yet,
And tye a ribbon round his hat,
And, father, I'll gang wi' him!"
The first 2 verses of Burns' song seems to be based on the 2 above, and the last 3 of Burns' song really have nothing to do with the old ballad.