"Suffolk Miracle, what's the title of this one? Young Buchan calls it "Derry So Fair" in this thread (click), but wasn't completely sure about the source."

It appears in Robin Morton's book Folksongs Sung In Ulster,and there is a recording of it on Volume 1 of the two volume LP set of the same name. I have a copy of both, but cannot easily lay my hands on either - moved house last year and much stuff still in boxes!