Well I would be pretty sceptical of anything you see in The Pick Up Artist, and yes, there are parts of England I've been to where you just can't risk approaching too many women. I've been glassed when I was in Sheffield for approaching someone's girlfriend inadvertently. It's frankly a miracle that I'm not disfigured and that the scar is virtually invisible.
However, MOST women in England are perfectly friendly in my (admittedly somewhat limited nationwide) experience. You've just got to use a bit of sense, try day game or just go to a nicer part of london.
And yes, American people as a general rule are extremely warm, friendly and courteous and the women are very receptive especially if you have an English accent like mine

Of course, I am sure there are exceptions.
Oh and don't use weird routines, be natural, its a lot better and less creepy. English women in particularly will rip the piss out of you and make you look like an idiot if you try to read their palms or any of that crap.