...Had Hitler, according to Churchill's own words, attacked from across the English channel when England had hardly anyone at home to counter an attack. But, Hitler balked & the rest is, well, history.
True. Immediately after Dunkirk, the Nazis paused...indeed, AT Dunkirk, the Nazis relented.
And in the Battle of Britain, the Axis switched from military to civilian targets at a moment very fortuitous for the RAF. Similarly, they relented and left at just the point when they could have killed the RAF (Hitler was already impatiently looking eastward). It's true that the Germans had no suitable landing craft (just modified barges and such), but finishing the kill of the RAF and successfully blockading the island (without convoy assistance from the States) would have been a TKO, even without Sea Lion.
Yeah, on land. You forget the Royal Navy. As Churchill said "We are looking forward to a German Invasion. So are the fishes"