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.
I believe it was code named Operation Sea Lion by the Germans. They paused because Hitler was more concerned with attacking Russia.
You forget - it was also nice that the Germans forgot to keep bombing the radar stations.
But the whole idea of the battle of britain being vital to the defence of Britain is a war myth. It was useful, but Seelowe was doomed even if the Germans had not invaded russia, and had spent four years building landing craft. Let me explain.
Four years later, D-day was sucessful against fair german opposition. The germans had little air-power in theatre. They had no heavy mobile armour near the beaches as we know. But the allies weren't facing two hundred destroyers, twenty odd cruisers, twelve battleships - do I need to draw a picture here? The Wermacht would have been fishfood.