I can not be certain that barbs will attack an angel, but would expect that some would. Angels are very often victims of fin nippers. They often suffer fin damage from other angels as well. I don't know if shop keepers in Australia are any better but here it is difficult to find a medium or large angel with it's fins at their full potential.
The angels in my avatar were purchased at a body length of 2-3cm. As they matured a third one was beat up pretty bad and it's fins haven't fully recovered (approximately 7 months now) despite being moved to another tank.