On the acoustic version Simon sometimes plays a different version of the song.
I think ive worked out the riff for it which can be used in the intro and verses :)

e|----------12\-|
B|-10-12-10-----|
G|---9--9--9----|
D|--------------|
A|--------------|
D|--------------|

e|----------------------0--|
B|-10-10-10-10-10-10----10-|
G|-9--9--9--9--9--9-----11-|
D|-x--x--x--11-11-11----0--|
A|-11-11-11-0--0--0--11-0--|
D|-------------------11-0--|