One of the reasons the Nazis could not invade Britain is that they never developed a landing craft. Nothing even like the Higgins boat much less a LST, so they were reliant on capturing intact an English port city. The English were well aware of this and had wired all dock facilities for demolition if invasion became imminent.
Following the Battle of Britain they never again held air superiority, so their tactic of invasion by paratroops as in Greece was out of the question.