have been/for a while

DollI have been at this London for a while.--- Saying this London doesn't sound correct to me.

I have been to the London for a while. --- London doesn't take the.

I have been for a while in this place.

Dear Gary,

I didn't say I have been to this forum for a while is correct I just said that I have been here for a while is correct. Besides, semantically and logically you can't go to a forum. You can just visit, log in, enter or be there.

And read my comments again because when you sent this, I was editing my post to add more explanation.

I met Mr. A who is an african in my country.

Myself : Hi, Mr. A, Have you been here before this visit?

Mr. A. : I have already been here six times. This is my seventh visit to India.

Myself : I too have been in your country twice.

Pleasecorrect my sentences.

Hello Nona,

Does all incorrect include below or above sentences?

User Gary's 3 London sentences were incorrect. I provided a couple of correct ones. then I also amended his next set of sentences.

Thanks gor your reply.