Every time the phone was plugged into the computer iTunes would say that there was an update for the carrier settings, but it never applied and the menu entries remained blank. O2 support were only slightly helpful, taking me through the settings which appear on their website but not fixing the Visual Voicemail issues or the prompt in iTunes.

There are threads on the O2 site here and here and a useful one on AVForums which gives the fix.

Unfortunately the fix is to completely reset the iPhone and start from scratch. Restoring from a backup simply brings the old (broken) settings back. I couldn’t find a way to only synchronise contacts back to the phone, though iTunes suggests it is possible.

Follow these steps to repair it:

1. erase the phone from the menu: Settings -> General -> Reset -> Erase All Content and Settings
2. connect the phone to iTunes and restore iOS4
3. set the device up as a new phone, not from a backup!

Browsing through the carrier settings menu should now show the correct values for APN (idata.o2.co.uk). Importantly, the Visual Voicemail settings should also be in the menu.

Now to setup all my apps, account sand contacts from scratch..

Big thanks go to Simon from the company who responded to my queries very quickly.

Some of the more popular old content has been moved over, old links should work. Older content which was not often visited has been purged. If there is something you want from the old site, please email me.