Did more British people own guns back then? Taking over a country, especially an island, that isn't just a tiny fraction of your own size is simply an impossibility unless the country really, really, hates it's govt. So, there's no way Germany can occupy England unless England has a population of like 3-4 million and hates it's government to the point of a near revolt.
A little off topic, there's a cool documentary on Comcast's On-Demand about WWI and America's relationship toward England and Germany.
I never really knew how popular Germany was at the start of WWI. We were selling them goods, our economy was booming. An early version of a German submarine snuck through the British blockade and made it to America. They were treated like heroes by the people (some members of our Govt objected), and then we loaded up their ship with nickel and rubber (don't ask me why they wanted those two items so much) and sent them along their way.
Germany, whether WWI or WWII just miscalculated America every time. Imagine if Germany hadn't invaded France. Instead, the very first thing they do is manufacture a conflict with Russia, get Poland's permission to cross their country, and attack Russia. If Germany had done that, America would have created a lend-lease program *for* Germany to crush Russia. Then, spend a couple of years, maybe ten, converting Russia to National Socialism. After the mess that Stalin made, those Russians would have thought the Nazi way of life was a gift from god. Remember, the Nazis were efficient and knew how make a country run like clockwork. Then imagine Hitler going after the rest of Europe, with the might and resources of his new Russian territories behind him instead of fighting against them.
Yikes, it wouldn't not be pretty.
PS, sorry for long ass post, I forgive anyone who just skips over it.