Yes you should change the Cellular Data APN to mobile.o2.co.ukIt's only down for the idata.o2.co.uk login by the looks of it, as I could connect to the internet through tethering through the iPhone fine - but not on the iPhone.
You never know they may be upgrading the service ha ha ha...as if.Yes you should change the Cellular Data APN to mobile.o2.co.uk
Go to Settings... General... Network... Cellular Data Network
The o2 forums seems to suggest that this is what some people are being told to do by o2, but only for 24hrs (this might just be because they hope things will be fixed by then), though some also add that o2 have told them they may be charged for data via this APN, though if they contact o2 these charges will be cancelled.Had to change the APN to mobile.o2.co.uk what ever that is. Will that screw anything up?