>Jack Armstrongs first recording was in 1949 - a 78EP called Chevy Chase/Rothbury Hills.<

Of course he did. Sorry, my mistake, although it would have been a single, not an EP.

>As for using the ballad tune as a theme for something more complex. That would work, I've seen a number of variation sets for it but all within the NSP world.<

Not being a musician I'm none too sure of the mechanics of recomposition, but I think you're right. As a matter of fact, Ewan MacColl was given to recasting his own melodies out of traditional tunes. EG., you'd never think it, but the Shoals of Herring, Freeborn Man and the tune which accompanies the leaving hospital song, from the radio ballad, The Body Blow were all developed from the melody for The Famous Flower Among Serving Men.

Incidentally, I'm not trying to make a case out for saying that Eubie Blake composed his Chevy Chase out of the Northumbrian original; merely that it strikes me as possible, and I was wondering whether anyone might know one way or the other.

Also, the fact that I can hear no resemblance between the two is neither here nor there. I can't hear any resemblance between the three MacColl tunes and TFFASM either.