One also wonders what the British government's emphasis on science will do in the future, after the war. Would it be Wilson's "White Heat of Technology" or Lewis's N.I.C.E.?
Uhhh, I'm afraid I don't have enough information on those two speeches to make a conclusion. But the title of Wilson's speech sounds like the one.
A suggestion. The huge cost of the Manhattan project was mainly due to the decision to cover both options, the U235 bomb and the Plutomium bomb, the U-235 bomb being about 3/4 of the total cost. That was OK in OTL, the allies had the money and resources to cover both bets.
Now if, as part of the extra scientists, a POD occurs which makes the Plute bomb look a better prospect, the Empire could fund the project without totally disconnecting its war effort - it would only cost around £125M in 1940 prices. Maybe a few less gifts to the Soviets would cover some of the cost.
In OTL, it wasnt realised until quite late in the British program just how much a U-235 bomb would cost, however if its realised early, and the Plute solution looks workable, its a reasonable change of plan.
What's the Plute Bomb? Also, was the U-235 designed specifically just to carry the bomb or was it designed to be a very long distance bomber?