It's good that you got out there and took some photos, an ice-breaker as it were.
How do you feel about taking photographs of homeless people on the street? Personally I would give the a decision a lot of consideration as to the 'why' before photographing such vulnerable people.
In general, I find taking photos of random people who provide the slightest bit of interest can keep me from rusting up on a walk, but they pretty much all get binned, more thought needs to go into the keepers and it will show.
If I were to comment on the photos individually
#1 - If the sign somehow provided a juxtaposition to the coat, it could be clever - but it doesn't, and you need to think more about your framing - even then I don't find his coat provides enough interest on it's own to make a photo, it just doesn't mean anything to me.
#2 - Not much to say, there could have been some interest if we could see emotion on his face that told a story. Maybe he's annoyed at people in the way, or tired of his job. But as it there's not much going on, and framing is not helping.
#3 - You've captured a story with emotion, nothing else in the image works for me.
#4 - Nothing of interest here, no story.
#5 - Camera angle looking down on a homeless person, I feel bad for the guy - not because of his predicament but because you took a photograph.
I would generally avoid ugly high streets with common brand names, unless you can avoid getting them in the photograph. London has plenty of more interesting people and settings to take photographs.
