"...Wasn't a multinational force, it was the Royal Army which was undiscrimanitng about where it recruited and who it hired..."

I think you'll fine that it WAS a multinational force:

The Army consisted of British (Including Ireland<1>) born British and American born British (including Canada) serving in the regular forces.
America Loyalist forces.
possibly Hanovarians (George III was heredetary 'Elector' of Hanover) forces.
German forces hired as complete forces from the various German princlings (Complete battalions as 'mercenary' forces).

As each little German state ('Lande'?) was a seperate state, surely that makes it a multinational force.

W

<1> Or bearing in mind the way "Sjt Want" and "Sjt Hunger" recruited - especially from Ireland