It was the chorus lines posted for Carnwuth Mull that I found to be similar to Mormond Braes. WNATBA was said, I thought, to be based on Carnwuth Mull. It's chorus as posted above...

   And its fare ye weel tae Carnwath Mull
   and its fare ye weel ma dearie
   o its fare ye weel tae Carnwath Mull
   for its there that a lost ma dearie.

is almost identical to

   So fare ye weel, ye Mormond Braes
   Where aften I've been cheery
   Fare ye weel ye Mormond Braes
   For it's there I lost ma dearie.

Reiver 2