Jim
Phil Tanner's Henry Martin certainly has some phrases in common with Derry Down but is completely different rhythm and format, superb as it is. Curiously FS of the Catskills also mentions Henry Martin so I will see if this links up.

For more than 3 centuries the Derry Down format has remained very true to itself, i.e., Anapestic tetrameter and an aabb rhymescheme, as per the excellent example above; if occasionally the chorus line is tweaked.