There was an unavoidable delay between my post about the MIDI of the old tune and the actual posting of the old tune. If you are reading this, please go up and listen to the old tune, because it's finally here.

Here's a musical puzzle. Recently we played the two versions of this tune, the familiar version in D and the older version which is posted above. I found it easy to specify chords (C,D7 G)to move from the 1810 version to the familiar version, but it didn't work going back.
Supposedly one modulates by playing the 5-7 chord of the new key, which in this case would be a G7, but it didn't sound right.

Another thing: if you want it to look Welsh, you put the chord symbols below the notes, not above. We joke that our guitarist can play guitar in three language, English, Welsh and German.