Erm didn't Silva want to be captured, so he could be brought to London and kill M?
There are much easier ways he could have got to London. After his escape, he went through a busy public train station on the way to the hearing. He could easily have gotten to London and that train station without such elaborate cloak and dagger. I don't see the logistical benefit to Silva of his capture and escape. I think it was all for show: he wanted to confront M face-to-face and to humiliate MI6 again.