I want to Become an Au Pair in England. Any ideas of towns I could stay?

Something about me. Hi! My name is María and I live in Spain. I would like to study a english philology degree (now its name is "english studies"). I really love English language, and I am sure I will like all about english-speaking countries. I know America is not like films show us, but in spite of it I can't wait to visit it. I think I am used to american english pronounciation, but I have watched some british celebrities videos in Youtube and it is easy to understand for me. But there are others, for example Adele, whose pronounciation is very difficult. I guess it is only about practise, as much listening as speaking. But where I live there aren't people with whom I can speak in english so...here I am :)

How can you, english native speakers, know the whole phrasal verbs? There is a lot of verbs made only with the conjunction of a verb and a "random" preposition...do you, english native speakers, really know all of them?