I've been thinking. Picking up on suggestions by others that if Islamic terrorists are involved they might be planning something spectacular for Remembrance Sunday: to have abducted Corrie for such a purpose, they would have to keep him confined for almost 7 weeks. I'm guessing that in this case, Corrie would have worked out that they planned to kill him and would have made every effort to escape or die in the attempt.
I also think it would be a very long time for there to be no "chatter" in the chat rooms and suchlike that are monitored by the security services. 7 weeks is a long time for any group, especially Islamaloons and their supporters, to keep completely quiet about something that would be as big as this.
The other thing that comes to mind is that while Corrie, simply as a serving UK military man, would be sufficient a prize for Islamic terrorists, he is too junior to really be of interest to, eg, the Russians or Chinese. However, he might be a suitable target for a dry run with a view to (a) obsereving the reaction of the UK authorities, especially the military ones, and (b) learning from this for a future attempt on someone rather more senior.