I've just upgraded to a Nokia 6233, on Orange, and it looks like it may have been a mistake. When you switch on the phone, it says "Phone restricted", and you have to keep trying and switch it off/on several times and hope that it will start. Then it occasionally fails to register the SIM too! I got through to someone in Orange tech support who knew what they were talking about (afer three who didn't!), and she told me that this is a known problem, first reported in June, and they don't have a date for a fix (Nokia have to develop it, and Orange have to test it - presumably better than they did the current one!). We tried a couple of things to fix it (putting in a SIM from another phone, and setting it to GSM only), but they didn't work. I'm going to stick with this one for a few days and decide whether to send it back. But my advice is to steer clear of the Nokia 6233.
Avoid the Nokia 6280 on the Three network too, I know three( ) people who have had problems with this arrangement, apparently it's something to do with Three having their own software on the phones.