The only issue picked up on Feedback was the question of whether less royalties could be earned from a trad. designation.
It was conceded that was not true, but argued that he would not earn as much in royalties if other artists recorded it subsequently.
End of discussion.
No mention at all of how the song could not reasonably be described as traditional at all.

That's very disappointing, to say the least. Does that mean that more people were concerned about the loss of future royalties to Seth Lakeman than whether his song is traditional or not?

How does that square with the fact that on the single, it is credited to him as the author, with no mention of "trad arr"?