The facts that you present are not 100% clear. It appears that you are stating that you went for an interview at the American Embassy in London and that as a result of that interview you were removed by the UK authorities to your home country of Nigeria. If this is the case, the question that will need to be aswered is what the status of your US visa application was at the time of your removal from the UK.
Since the facts of your case are not clear and there are obvious complications, I suggest you schedule a telephone consultation with an experienced immigration attorney who can review your case and assist you in obtaining your visa. As time if of the essence in diversity visa cases I suggest you take action immediately.
You need to notify the U.S. Embassy in London to transfer your application to the U.S. Embassy in Lagos. Neither factor that you mentioned should affect your eligibility for permanent residence in the U.S.