I used to sing this once and was just trying to relearn it today.

To fit with Dick Gaughan's key you need capo on 4th and play

Am Em Am
C D Am
Bb Am C Em
G D

close to what the original poster was playing. It's the 3rd line that I struggle with, but that sequence seems to work. I used to sing it in a slightly higher key with chords (no capo)

Em Bm Em
G A Em
F Em G Bm
D A

Gerry