It is perfectly normal - If the judge orders the person's extradition, he must remand the person in custody or on bail pending the extradition. He was granted bail by the High Court in London and was released at Stansted airport during the afternoon, where he boarded a plane and departed the UK.
In reality he is not "free" till the judge slaps their hammer down.
He was already in prison. Usually you do not let people go out to let them extradict themself.
It is a weird comprimise to put an end to this farce.