The tune in the DT is the original one from Pills to Purge Melancholy, so far as I know; if you don't recognise it, then you'll be looking for the modern tune written by Dave Moran that's mostly used nowadays, I expect; that's the one that Steeleye Span recorded, though they learned it from Tom Gilfellon who was under the misapprehension that it was traditional. Notation was published in the first Steeleye Span Songbook, if you can get hold of a copy of that. It's easy to learn by ear, though.