Basic rule of thumb for nosebleeds: Lean forward, pinch nose for 10 minutes (don't keep checking to see whether it's stopped!). If it's still bleeding, pinch it for another 10 mins. Check again, if it's still bleeding, pinch it for another 10 mins. At this point, it's now been 30 minutes since you started: if it's still bleeding, the casualty needs to go to hospital. In your case, you wouldn't necessarily need an ambulance - calling a taxi might have done the trick. If you've got a copy of the First Aid Manual that's issued by St John Ambulance/St Andrew's Ambulance Association/Red Cross, nosebleeds are covered on p125 (9th edition).