Thanks Trek No, the guy who called the ambulance actually did see her slip on the ramp and fall.

Ok, so I learned the following from this:
1. as long as no-one is screaming I can keep my cool
2. remember to check breathing immediately
3. people behave strangely after fainting, with some senses returning before others. This is ironic, actually, because I almost-faint all the time due to low blood pressure, so I know exactly how it feels to get tunnel vision, weak knees, stop speaking but still hear everything - I just didn't know it could be like that when coming to as well.
4. don't let the patient decide what to do, or their helpful family, unless you agree. The husband got her on her feet once and sitting once before she was ready, and both times she could easily have hit herself harder blacking out again. And she was talking about being fine and I could go, when she was very obviously not ok (eyes closed, mumbling).

Ok, I'll stop re-hashing this now Thanks for your input folks!