As to 'Are the Brits friendly' the diatribe above was primarily (correct me if I'm wrong) about London. There is more to England, or Scotland for that matter, than London. A large percentage of the population of London are foriegners so if you put yourself in thier shoes I'm sure they get tired of hearing a foriegn accent out of every other person they talk to. It is probably wearing on thier hospitality to have peoples from around the world on thier doorstep.
In my own experience I have had some heartwarming, funny, and very welcoming reactions to being Canadian in the
UK. I was told by a shopkeeper that was I aware that whenever Briton was in trouble Canadians, Australians, and New Zealanders were always there to help out the 'Motherland'? Never having thought of England as 'the Motherland' I was at a loss for words but I just smiled because he seemed to think it was something to be proud of. Another time an oldster on the bus asked me if I was Joe Somebody's Mrs. as he has an American wife then was quite amazed that I wasn't.
Are the Brits friendly? Some are, some aren't. Go hang out with the nice ones and "always look on the bright side of life da da da da da da da da !"