I'm relatively satisfied now that there is one person, seen in 4, 5 and legs in 6, who is "patrolling" the area. This is the individual who knows something.
In 6, do they stop and turn to watch the runner, or do they stop and turn to make sure the runner passes the hotspot (Horseshoe) that they have been patrolling.
They've done a good job of hiding their identity, using hood and sticking to the walls and out of the light (for CCTV camera detection). But what they hadn't counted on is that frequency and retracing steps no matter whether you are identifiable or not, also gives a lot away.
The guy running could have a major clue. If he knows who it was down the alley that made him run on the right hand side to avoid them, he may know who this Horseshoe patrolling so-and-so is. It could be possible that others are aware of this patrolling person, even if they only know this patroller from that night only, for example it may only have been this night that Brentgrovel had a person loitering and these people, as locals, noticed that (even subconsciously) hence Corrie's apprehension, the running man staying to one side, etc.
Ok thats very speculative, but I think, with this new CCTV footage, there is reason to believe that someone is loitering up and down Brentgrovel street that night, possibly with bad intentions. A person who knows how to use the shadows and to obfuscate the CCTV. That person may also have thrown the phone in the bin. Sadly, their fingerprints (though it looks like this person may be wearing gloves) would now be at the bottom of a landfill.
Edit, about the legs, apparently " the police are aware of this person." But that doesn't mean he/she is identified yet.