@darkscarIf you want partially occupied England, and stalemate, you need different, inconclusivde outcome of WWII, an for that you need different leadership in at least key players.
Let's start with my favorite alternative history forking point: let's say, Stalin's court coup fails, Lenin's last wish stands true, and Trotcky becomes First Secretary of the USSR. He would continue Lenin's started course of reintroduction of individual entrepreneurship and restoration of private property (what Stalin killed, in bloodshed) and, we may assume, USSR would do basically the same Chinese did roughly 80 years later, with comparable economic outcomes. Moreover, he wouldn't kill seasoned generals in charge of the army, (including Latvians among them), and with sufficient funds and competent leadership the reforms and rearmament would be done in time.
Also, Baltic states are incorporated more intelligently, initially leaving a lot of cultural autonomy. Winter war in Finland is swiftly and decisively won, if happen at all. Finnish Socialist Republic becomes something alike later Warshaw Pact countries.
Meanwhile, Hitler didn't want to invade England, he adored their way of life too much. That's why evacuation of Dunkirk was allowed, Hitler hoped that will eventually lead to separate peace talks with Great Britain. But let's say, he knows USSR is much stronger and better prepared, and so he must secure his backyard before going east so he authorize Sea Lion instead of Barbarossa, Dunkirk is done with in much more conclusive manner and ground invasion in England began. It isn't so easy going as previous campaigns, but progress is made, and the outcome seems inevitable...
Fall of London is all the pretext USSR (who is ready for the long planned war by then), needs to launch wide scale offensive against Germany. German occupied Poland change hands in a matter of days. Properly deployed T34 divisions are unstoppable by Mark III and Mark IV, it just deep in Germany that Russians are bogged down and forced into more positional warfare much resembling First Great War, but not before roughly the extended of Warshaw Pact borders known to us are reached. Fulda Gap doubles over for Kursk, and Berlin itself for Stalingrad, both with roles reversed. Except, Germany simply lacks resources for using that for counterattack.
Invasion forces from England are recalled home, perhaps even a hasty ceasefire is signed. Since there's no US forces in Britain at this point, and it seems like a narrow escape, while a hope for later help exists, that's somewhat plausible.
Meanwhile, Rommel roam in Africa and Middle east supported by Italians, as lame they are, but largely unopposed, also, that's now the Germany's only hope to secure some oil.
Perhaps, Berlin even eventually fall, but that's it, USSR even from better starting positions is winded out by then. Since they wage aggressive invasion, there's no Lend-Lease help from US, and invasion is much harder to sustain and justify, especially for significantly more free public.
Meanwhile in the Pacific things proceed almost identical. Only, US is way less committed in Europe, although they do aid in defense of unoccupied part of Great Britain, that's about it, although talks about eventual counter offensive exists. Eventually US move a bit more swiftly, reaching Japan islands before A-bomb is ready, and launch ground invasion in Manchuria instead of D-Day we know.
Also note, there's no Soviet campaign in far east, they are still besieging Berlin, faced with growing war weariness and turmoil at home. Perhaps, hardliner communists use that for another coup, with only hamper the war effort further.
Meanwhile, Hitler is killed in successful assassination by largely the same branch of military aristocracy, and the war hero, successful conqueror of the middle east, Rommel becomes the new fuhrer. However, his first order of business is secret peace talks with Soviet Union...
Meanwhile, presence of US troops in Scotland is successfully framed as occupation by underground propaganda, and socialist revolution looms...
Well, I will fade out here, because, as far as we got, all guessing is off already.
