Just finished reading it. I liked the detail and found the plot both enjoyable reasonably plausible... with three huge exceptions.
You've allready written your book, which is more than I ever did with any of my TLs, so it seems somewhat churlish to criticize, but I will do it just the same (spoilers follow in white-type).
1. It seems to me incoceivable that Britain would divest itself of Empire, and India in particular, with Japan rampaging through China and Indochina, and the Nazis at the Urals
2. That Hitler would stumble into a war with the U.S over the Azores without first trying to Neutralize Britain (which in and of itself could be the trigger for war with the U.S) seems even less conceivable.
3. Finally, the Soviets rebuilding a functional state behind the Urals, engaging the Germans in large scale combat, and doing all this without the Germans in Azerbijan realizing that the Brits were resupplying them or taking steps to complete the destruction of the Soviets seems far-fetched. The survival and relatively good performance of rump CHina to 1945 with Japan neither starved for oil nor engaged in the pacific war seems only slightly less plausible.
(as an aside, that a Pakistan would come into existence without the Brits birthmaiding it also seems unlikely. Nehru would simply crush the muslim sepratists with the Indian army, and the bloodside would be relatively one sided. The only reason this didn;t happen OTL was that the British divided the army and determined the borders before leaving. If they simply hand over the keys to a majority government then the majority crushes the minority
Likewise a managed population transfer of ALL Muslim Palestinians to the Transjordan, even in the immediate aftermath of crushing the Great Arab Rebellion is also unworkable. Transjordan simply couldn;t support them all and a loyal British client would be royally ticked off and shoved into the axis camp. What COULD perhaps be done, is a managed population transfer involving Assyrians as well as Jews from Iraq to Mandatory Palestine. Iraq had the land to to support the Palestinians and the position of the Assyrians, who the British maintained as clients but were unable to protect from massacrres, was precarious. Something similiar versus Egypt, perhaps with Copts being concentrated in the canal zone might also have been managed.)
The thing is, I think you could have maintained your plot and theme without these blunders. Simply have Britain take steps towrds imperial divestment in the 1940s but wait for full implementation, particularly in India (perhaps dominion independence coupled with a defense alliance?), have Hitler invade Britian in retaliation for their revealed support of the soviet rump (and Japan do the same), and then have the U.S intervene, either immediately or following the resumption of submarine warfare.
