Well... my text from O2 came today.
The unlock process appeared to go very well. With the O2 SIM in I connected the phone to iTunes, and did a restore. Got the congratulations message to tell me I had unlocked my phone. I disconnected put my Orange SIM in and reconnected. I was asked if I wanted to download carrier settings, which I did.
All appeared OK. However, I couldn't launch any apps. The default apps (maps, mail etc) are all OK, but all the ones I've downloaded from the App Store just crash when I open them - all of them.
I did another restore, this time with the Orange SIM. Again got the Congratulations message, followed by a request to download carrier settings. Same thing. All my apps open for a split second then crash. I've got about £50 worth of apps so I'm hoping that I don't have to buy them all again.
On both Restore processes I Synced the phone from a backup. I'm loathed the set it up as a new phone as I loose all my achievements on my games, but if that is what I need to do...
I've tried resetting the phone but that's not worked.
I downloaded a new app and that also crashed on opening.
Eek... help...