Regent St. Apple store has a full calendar of events on the 11th, which they definitely didn't for the first iPhone.
It's not like they can't change them: Friday 11th.
10:00 am - 11:00 am Mac OS X Leopard Workshop
11:00 am - 12:00 pm iWork '08 Workshop
12:00 pm - 1:00 pm iPhone Workshop
1:00 pm - 2:00 pm iWeb Workshop
2:00 pm - 3:00 pm iMovie and iDVD Workshop
3:00 pm - 4:00 pm iPhoto Workshop
4:00 pm - 5:00 pm GarageBand Workshop
6:00 pm - 7:00 pm PC to Mac Workshop
7:00 pm - 8:00 pm iLife '08 Workshop
Usually the majority of the audience at Regent Street is there for the comfy seats and free wi-fi. I'd imagine the shop is going to be buzzing with iPhone, and the above schedule is subject to change.
The shop is going to have a huge crowd trying out the new iPhones, purchasing them, the 3G iPhone ads will be being added to the stock reels if it hasn't already... They could actually easily have a full day on 3G iPhone and still keep the schedule:
e.g .the 11am slot, 12pm slot, 6pm slot.