OK, this seems to be hit or miss and online sites all claim Apple states this is because their servers are overwhelmed. I guess the upgrade procedure, even though the update is local, contacts the Apple servers and it isn’t getting a response.
A colleague of mine tried a few times and then it went through like normal. I tried mine about 6 times with no success. Instead I held my Shift key down and selected Restore. Normally you only do this when you want to restore to a prior version. Happily iTunes asked me where the file was and I pointed it to the new iOS 5 update.
It wiped my iPad, “restored” it to iOS 5 and then, quite to my surprise, reloaded all of my apps and data. Not only did I not lose anything but I didn’t even have to reload my apps or restore my data manually.
All in all it went well.
Off to do my iPhone.
