These are the two I know - might not be very accurate, just scribbled them out:
Firstly the 'popular' one:
T:Holly&Ivy1
M:4/4
L:1/4
Q:100
K:G
GG/2G/2Ge|dBG/2G/2G/2G/2|Ged2|d/2c/2B/2A/2GB/2B/2|EDG/2A/2B/2c/2BA|G2

And secondly the 'folksingers' one, much, much nicer in my opinion:
T:Holly&Ivy2
M:6/8
L:1/8
Q:100
K:G
GA|BAGDGF|G3G2d|d2BGAB|(A3A2)d|d2BBAB|c2ccdc|BAGDGF|G4
Would be interested in the third one, Sian, can you put the abcs here please?
Jo