this ties in with what I said in my post... that the UK didn't have the manpower to invade the Continent soon... not 'never'. A Germany that has been severely reduced after a long grinding war with Russia is another story
Okay, fair enough. On the Germany being reduced part, I'd still say the German Army of 1944 waxes the floor with the 1941 German Army, so manpower isn't everything
I could see the UK eventually invading France to keep it out of the hands of the Soviet juggernaut that is overrunning everything else in Europe"
Without the heavy German buildup in the west in preparation of D-Day - and the invasion of Italy prior to - the Germans would have kept a lot closer to the 3,000,000 they had on the Eastern Front at the Battle of Kursk, rather than the 1.9-2.0 million IOTL around May 1944, so there wouldn't have been a Soviet steamroller, not yet anyway (if ever; without a second front), rather the Soviets would have broken through for the same reason they did in the OTL, because of German forces being transferred west to deal with the new theater in France. Likely you have a stalemated Eastern Front, with the Germans not having to pull out the II SS Panzer Corps - and other divisions - at the height of operations in order to transfer them to Italy for the Allied invasions.
the UK might have had 2.5 million men, but they could scarcely gather them all up to throw onto the Continent... logistics and requirements elsewhere just don't allow it."
Defeat the Japanese Navy or sign an armistice with Japan, and you absolutely could. Hell they may even had enough to pull it off just with what they fielded in Europe and Italy (Second Army, Canadian First Army, Eighth Army, I Airborne Corps, and the 4-5 divisions still kept in England to make Hitler think they were going to attack Norway; Second and Eighth Armies were massive formations btw, both about the same size as U.S. First Army). I'll give you a run down of the Empire's forces. For comparison, remember that U.S. First, Third, British Second, and Canadian First Armies were enough to crush the Germans in France.
I Corps in North-West Europe
II Corps in Britain (only 3 divisions)
III Corps in Persia and Iraq Command by 1943 (only 2 Divisions and a Brigade)
IV Corps in India/Burma
V Corps in Italy
VIII Corps in North-West Europe
IX Corps in Italy
XII Corps in North-West Europe
XIII Corps in Italy
XXX Corps in North-West Europe
I Airborne Corps in North-West Europe
(more British divisions attached to the Indian Corps listed further below)
I Canadian Corps in North-West Europe
II Canadian Corps in North-West Europe
Indian III Corps in India/Burma
Indian IV Corps in India/Burma
Indian XV Corps in India/Burma
Indian XXI Corps in India/Burma
Indian XXV Corps in India/Burma
Indian XXXIII Corps in India/Burma
I Australian Corps in South-West Pacific
II Australian Corps in South-West Pacific
III Australian Corps in South-West Pacific
(Australian Army = 9 Divisions total; smaller corps than typical British, Canadian or Indian Corps, unless specified)
All in all we're talking over 5,700 tanks btw, pretty much just as many as the 6,300+ in the U.S. Army. Thousands were given in lend-lease from America, but then Britain also gave over 5,000 tanks to the USSR, so mostly a wash.