OKW was also concerned that the supply lines and flanks were vulnerable and Hitler really thought he could negotiate with the British and perhaps even swing them over to unite against the Soviet Union. And Fatso Goering didn't help matters boasting that his Luftwaffe alone could finish off the BEF.
Hitler also still held out hope that the Brits would “come to their senses” and get rid of Churchill. He originally thought Britain and Germany would be natural allies because of their mutual hatred of Bolshevism.
But when von Ribbentrop felt slighted by the Brits when he was Ambassador to Britain, he developed a burning hatred for them, and he was able to convince Hitler to hate them too.
I still believe that Hitler sent Rudolf Hess on his mission to Britain, and they were the only two who knew about it.
There was no way the German navy could mobilize or support a reverse Operation Overlord. It took the better part of two years for the allies to marshal the men and equipment for the crossing. The allies didnt have much opposition in channel or in the air. The British navy and coastal air defense would have inflicted heavy losses if Operation Sea Lion had ever been attempted. Hitler did the right thing by listening to his admirals.