I have to disagree. While I do believe that conquest of the two Western countries (France and UK) was not something on the agenda in the first place as Hitler's interest lay entirely in the East, I think the attempt to occupy Britain was serious. Occupying it was the only way to put at least the heart nation of the Empire out of action and free enough ressources for the East. Otherwise the arial campaign would have made no sense as serious attrition took place. And you don't go on an all out campaign if it is just for teasing when you actually want it only for the real thing.