This is my first post too so hope I'm not repeating what has been said before.
I think it's important to look at the chain of events and think what is the most likely sequence of events. We know Corrie went out later than planned because he was on the phone to his brother. He got into town and went to a couple of bars looking for his mates and then went to Flex nightclub which is where they would normally go. Were his mates there? I don't think that has been stated. We don't know if he found them there, but we do know he was asked to leave; that was unplanned. He then follows a normal routine and gets something to eat. After eating a large amount of food and having had a fair amount to drink he feels sleepy and goes to sleep in Hughes doorway. This seems unusual behaviour but perhaps not surprising given the amount of food and drink he has consumed.
He then wakes, presumably because he gets a message on his phone and that wakes him up. What is the first thing he needs to do having had quite a bit to drink? I would say he is busting to have a wee. He can't do that in Hughes doorway, it's too public. So he trots down to the horseshoe area. He has a quick scan around, then sees it is a quiet and dark area to have a wee. He walks into the area and looks a little sheepish, maybe because he is going to have a wee in public.and tried to look casual, hands in pockets etc
Then something happens in the area. The most likely thing to me is he sees something or someone who doesn't want to be seen. As a few others have already posted, the most likely thing is a drug deal or someone waiting to make a deal. The person or persons doing the deal panic and Corrie is punched and rendered unconscious. Do they then put Corrie into one of the bins? I think it unlikely that a single person could put Corrie into one of those bins. Corrie weighs 85Kgs, which is a lot to lift by one person to the height of the bin. This would mean two people must have been involved. Is this when Corrie's phone dropped out of his pocket, which was then thrown into another bin, the recycling bin?
On the CCTV someone is seen leaving the area 4 minutes after Corrie went in. Was that person seen going into the area? If two people were involved then was anyone else seen entering the area on CCTV?. If it was a drug deal the people involved would turn up, do the deal and go, no hanging around. It would be arranged on pay as you go phones so difficult to trace.
So if we take what Uncle T says as fact that Corrie could not have left on foot, then it could have been a vehicle or one of the other bins. A question that has not been answered (I don't think) is when were the other bins emptied, and where are they emptied? Could Corrie have been in one on those bins and not been spotted when it was emptied?
Just my thoughts...