Please, always write "you" properly. It's a mistake to use "u". Also, please pay attention to capital letters. Ignoring them means you are misspelling words. The correct answer is, "Have you ever been to London?" The examples of "been in" are usually translation errors, ie. using a grammar pattern from another language. The reason we use "to" is that there's a transit involved. The difference between "been to" and "gone to" is simple: "been to" means you went there, then left later.

"Have you ever been to London?" is correct