Well when I bought my phone the guy got the code emailed to him?? And they usually charge quite abit, so I would just suggest going to a phone shop to get it unlocked. It will most likely be cheaper than the £30 the operator asks for.
what do you mean 'online as opposed to using the phone'?
when you get the code you're going to have to put it in the phone...
have you tried calling 02 and asking do they have the code?