Well Digby, the game doesn't cover the Grand-strategic, geo-political, economic, or naval aspects of the situation.

The designer has just given a possible situation showing that Napoleon's forces have arrived in England. So players now have the opportunity to see what it may have been like had this actually happen. (Within the the limits of the game system, of course.)

Kind of like all the 'what-if' books and games concerning Operation Sea-Lion.

It's one of those "accept the premise and think about the possibilities of the question" type of thing.

al