No Battle of Britain, go straight up from the Fall of France to Barbarossa. Contact the Italians about the need to avoid meddling in Greece before the end of the war and contact the Japanese about seizing Vladivostok and promise oil. Work to avoid the Yugoslavian coup. Good chances of winning.
The other route is to capture the BEF if possible, then a compromise peace could've been achieved with Britain and Germany could focus in the east. But then the USSR wouldn't been caught by surprise, and they are the most important and dangerous enemy of the Reich. The Germans may not have reached so deep in Russia if the soviets had prepared their defenses accordingly.