In reply to Greasy Prusiks:
I downloaded this and a similar St John's app last year. They're quite nice, but, essentially, they are books. They missed the opportunity to use the computer to deploy some expert-system-assisted triage, to guide a trained first aider (or novice) down a diagnosis tree for common ailments. By presenting a list of first aid treatments for major ailments, they have already assumed the first aider is able to do primary diagnosis. I think I would have preferred a tree-based system (or at least an option to explore one), using the basic 'Breathing, Bleeding, Brain, Burns, Bones'.
The St John's app boots into 'Emergency' mode. The Red Cross app boots into 'Learn'. A simple difference, but could it be important; if you're not in an emergency situation, that extra step to switch to 'learn' isn't a problem. If you're in an emergency situation, you want the fewest steps possible.
Again; they're useful apps, and I have all three on my tablets, but they could be so much better.