I've worked out the chords - the primary differences are in the first two lines. I'll try writing it using Rise Up Singing layout. I just bought a ukulele and am experimenting with it at work, so using CDG chords:

Scotland the Brave:

GGGG
CGDD
GGGG
CGDG

becomes John MacLean's March:

GGCC
DDCD (could also be DDGD?)
GGGG
CGDG