If Britain didn't fall in this fictional scenario and the US still developed the A-bomb I wonder if Wilhelmshaven would have been the logical first victim of its use on a military target? It's a coastal city within reasonable flying distance of bases in Britain and it has significance as a major German port for the Kriegsmarine during the war. With the A-Bomb and a way to deliver it I don't see even with the loss of Russia to the German forces a negotaited peace between Britain, US, and Germany...