Written on: 27/07/2013
Code came quickly (within 6 hours although they advise it may take several days). So easy to do.
Only problem is that you can't unlock without having an alternative sim to hand as the other methods to bring the menu no longer work on the s3.
If you Google everyone else has the same problem - something to do with a firmware update. They should update their instructions to reflect this but it is pretty minor.
Once you realise that just stick in another provider's sim and takes a minute max to do.