LAND O' THE LEAL in the DT is the Silly Wizard version, without attribution. Here's Lady Nairne's original from Charles Rogers, Life and Songs of the Baroness Nairne (London: Charles Griffin and Co., 1869, pp. 3-4):

    THE LAND O' THE LEAL
    Air--"Hey tutti taiti."

I'm wearin' awa', John,
Like snaw-wreaths in thaw, John,
I'm wearin' awa'
   To the land o' the leal.
There's nae sorrow there, John,
There's neither cauld nor care, John,
The day is aye fair
   In the land o' the leal.

Our bonnie bairn's there, John,
She was baith gude and fair, John,
And oh! we grudg'd her sair
   To the Land o' the leal.
But sorrow's sel' wears past, John,
And joy's a-comin' fast, John,
The joy that's aye to last
   In the land o' the leal.

Sae dear that joy was bought, John,
Sae free the battle fought, John,
That sinfu' man e'er brought
   To the land o' the leal.
Oh! dry your glist'ning e'e, John,
My saul langs to be free, John,
And angels beckon me
   To the land o' the leal.

Oh! haud ye leal and true, John,
Your day it's wearin' thro', John,
And I'll welcome you
   To the land o' the leal.
Now fare ye weel, my ain John,
This warld's cares are vain, John,
We'll meet, and we'll be fain,
   In the land o' the leal.