Hi,
I too am interested in that line! My ancestor, Mary Learmonth, was from Prestonkirk, East Linton - daughter of Peter Learmonth and Elizabeth Richardson. Peter was the son of Alexander Learmonth by his second wife Jean Foggo. These latter were from Haddington and Peter was born there. Alexander went on to marry again, an Elizabeth Dewar - their first child was born in Haddington and then the family moved to Spott and finally settled in Presonkirk in the early 1770s. The family lived at Markle Mains or Fortunebank farm. Peter's half-brother, Robert Learmonth (d.1860), was a well-known local farmer and auctioneer. In a local exhibition, the following was written about him: "His family is said to have been connected with Thomas Learmonth, the rhymer of Earcildone (Earlston), and James Learmonth, the convenanter who was executed in Edinburgh in 1678 for having been present at a meeting of one thousand persons for worship at Whitekirk Hill..."
I hope this helps! The Prestonkirk Learmonths were indeed from Haddington, and if James Learmonth was from there, they are likely to be connected. How exactly, I don't know! However, it is also pleasing to think there is a link with Thomas the Rhymer! If you are related to these Learmonths, I would be happy to find out more from you and about how we are connected.
Yours,
Ross.