The Channel Islands are not part of the British Isles, despite what Wikipedia says (there’s a long running dispute about this)
The German plan for a landing force of 27 divisions with half of them in the first wave is entirely unreasonable. Again, Overlord only had 5 divisions in the initial landing wave. The question you’re answering isn’t 'what would happen if the Royal Navy disappeared’; you’re answering 'what would happen if the English Channel disappeared.’ Sandhurst has wargamed Sea Lion as planned as if the Royal Navy didn’t exist, i.e. the exercise starts with the Germans landing on the beaches without having been blown out of the water on the way across. In every case by D+3 the Germans are holding onto two small isolated beachheads, facing forces greater than their own with the odds getting worse by the hour while still drawing supplies over open beaches.
So what? The whole OP is unreasonable. But if one accepts that invasion succeeded, it not unreasonable to accept that the Germans would win.
Exactly. If the OP asks “What if the Confederates had an atomic bomb like the one that blew up Hiroshima?” it’s on-topic to discuss what target they might have tried for or how they would have delivered the bomb without aircraft or missile technology. But a discussion on the state of 19th century physics and the impossibility of the OP would be off-topic. You have to accept the premise.
I’m feeling a little guilty about the grief you’ve been given over your opinion. I posted pretty much the same as you in post 17, but you’ve caught all the flak. Um, thanks. 
They build a giant oak barrel around it, label it as bourbon and drive it north on a heavy wagon.
I’ll admit I can get to arguing sometimes. I tell myself that it was the other guy that started it and he’s the one who’s got a problem. But he’s probably saying the same thing about me. At some point, my better nature reasserts itself and I just walk away.
And allow William T. Sherman to capture it and knock out the bung. 
They can land in Ireland first. Or even Norway or Iceland. You might as well assume the Atlantic belonged to the Brits.
If it’s on DVD, it will have subtitles . In English, but as you can see I can manage to read it.
Unfortunately, after reading your post, I tried to order it but the place where I usually order foreign DVDs has discontinued imports from the UK (in fact, from everywhere except the USA). I can’t order it from the UK online, either, because my bank has blocked all online transactions for customers who don’t suscribe to its SUPER SECURE (inconvenient, costly) online scheme, so I can’t order anything within the EU anymore. Fortunately, I can still use it for transactions in Nigeria and such places.
However, if it exists on DVD (I didn’t expect it), I’ll find a way to get my hands on it. I’ll try ordering it from a British library in Paris.
Damn, how did I miss this one? I’ve got to see this movie.
Another good “England invaded” work is An Englishman’s Castle.
I just read this; you can find it in Forester’s WWII-related short-story collection Gold from Crete. It’s pretty good.
German surface warships and U-boats are able to fend off the Royal Navy just long enough for the invasion fleet to get across the Channel for landings at Rye and Winchelsea (Rye, East Sussex - Wikipedia and Winchelsea - Wikipedia), but then the Luftwaffe can’t maintain local air superiority long enough to keep the invasion force adequately supplied. Home Guard units are more effective against the invaders than anyone expected; snipers, in particular, take a heavy toll against German officers. In the end the Germans are cut off in the British countryside, run out of gas and ammo, and are forced to surrender, still quite a distance from their objective, London.
Gold from Crete also includes a somewhat-related short story, “The Dumb Dutchman,” in which
a Dutch tugboat captain who’s secretly spying for the British feigns support for the Nazi cause and gets drafted into invasion duty. His tugboat tows several river barges with German infantrymen and equipment in them. During a nighttime practice run off the Dutch coast, he takes advantage of a heavy fog and the nautical ignorance of his Wehrmacht passengers to head straight across the Channel for Great Britain. A Royal Navy destroyer eventually stops them, easily suppresses the fire of some of the German troops, and captures the rest. The tugboat captain, who had been reassuring himself all along that, if worse came to worst, he could always commit suicide with poison concealed inside a pencil, is horrified to realize that he was carrying the wrong pencil all along!
Blitzkrieg don’t work without gasoline.
And there would be no resupply.
Period.
Yep, barges make poor tanks.
armies don’t seem to important when you can’t work out how the invader gets past the navy/air force combo.
Assuming the barges were going to make it, there were still last ditch ideas like effectively setting the channel on fire.
How does the saying go, amateurs talk about strategy, professionals talk about logistics?
Another aspect nobody has considered is the use of chemical warfare, by both sides. The Nazis planned a possible use of chemical/biological weapons feigning British use as a justification. However the British had no hesitations about use of chemical weapons as German troops hit the beaches;
This adds additional logistic pressure on the Germans in bringing over anti-gas measures and specialised medical treatments, or drains their not easily replaced manpower if they don’t bother.
Couldn’t they use one of the gizmos that turns other video media into computer files?
And to the person upthread who said something about infantry not being good against tanks - the Finns used molotov cocktails agains tanks quite effectively - who knew that if you dump a burning liquid into the vents on the backs of tanks it would cause the fuel and ammo to go kaboom … granted it can be sort of hard on the poor schlub tossing the molotov, but when you look at the stats for the Winter War, a bunch of antisocial Finns on skis with guns and molotov cocktails did pretty well.
I can’t help but think that the Home Guard would do fairly well against the Germans, after all Britain hadn’t started disarming the population at that point in time and there were a fair number of hunting guns and souvenir German militaria from WW1 knocking around. The pool of exWW1 doughboys might be pretty good against Jerry … as was pointed out upthread a few leftover grudges can do wonders for home defense. Nothing like practical experience and willingness to kill.
Not to mention, tactics is great, but remember the old saw about ‘Amateurs study tactics, professionals study logistics’ - resupply for the home team is always better than for invaders. A tank is great, until it runs out of fuel and spare parts…
Close, but these are the Germans we’re talking about.
Which could happen with a successfully blockaded GB, but if Jerry is smart enough to blockade them, he’s smart enough not to invade in the first place.
So my answer to OP is the Germans win because the only way it happens is the Brits have been besieged to the brink of starvation beforehand.
I’m sure the Home Guard would have acquitted themselves admirably, but it wouldn’t have been with their own personal weapons, because they mostly didn’t have any. The British population wasn’t significantly better armed before the war than it has been since.
… if they weren’t all safely at home in America.