I am concerned also (although it may shed light on why three sets of tickets haven't turned up yet!) It's really nice of the venue not to say anything. Reaaally nice. :)
I have found out that the Twickenham GA tickets are not getting sent
out to anybody internationally! Even though when I bought them from
ticketmaster there was no option for box office collection, and I had
to choose mail delivery.
I have had no notification of this from ticketmaster, and have tried
to contact them with no luck. I found this out from another fan on the
U2.com forums, and it does seem to be correct. Apparently ticketmaster
tried to claim that there are only 55 international GA tickets for
Twickenham...haha what a load of crap. It would be nice if this were
true because the box office line would be short, but I highly doubt
The Stadium Operations Department at Twickenham confirmed this, and
emailed me the following details for box office collection:
"The Box Office Collection point is at Gate A
You can collect at any time
Gate A is on Whitton Road
If you log on to www.twickenhamstadium.com you can download a concert
PDF which has all the maps you need."
You need to have you purchase number and the same credit card that was
used to order the tickets.