Congratulations! For interview, just feel relaxed and answer the questions directly. They are always the same questions such as Why MIF, Why LBS, Why now or What kind of the contribution you will do for the class. I suggest you should prepare your professional experience and related knowledge as MIF is more concentrated on finance.
I am sorry that I have no idea about the marketing course between these two schools. Both schools are very good at MBA teaching. You better check its website first to gain the first hand information.