I agree, the most likely logical answer is that he went to sleep in one of the bins where it would have been much warmer than a shop doorway. How sure are the Police that this scenario didn't happen? It seems too much of a coincidence about the route and direction of the ping from the mobile phone.
I think there remains a possibility of the phone in the bin that was emptied that morning and went on to its next pick-up in Mildenhall. We've been told there's a sort of correlation but not that it was a perfect correlation.
But, the actual bin that was emptied, and possibly contained the phone, was weighed at 11kg and was apparently recycling material. So it seems doubtful to me that Corrie was in that bin.
What are the chances of Corrie being in one bin and his phone in another? (An honest question, not a put-down.)