I think that the most effective course will be with professional native speaker teacher. When I was in UK(in London), I passed such one course and I can say that it was great experience. My results were great! I found this possibility here Learn English in London (United Kingdom) maybe you should pay attention to this variant.
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS