So let's say Dunkirk is a disaster for the Allies, and the UK makes peace with Germany. Italy still invades Greece in late 1940, with the same reasons and results as in OTL. In January, Greece asks for assistance from the Brits. Since they're at peace, Britain can provide everything Greece asked for IOTL. But will they, considering their situation? I'm really not sure. If they do, I assume Germany will want to send troops down right away, and my bet would be on German victory. But - what's happening with Yugoslavia? Are we still gonna see a coup? On one hand, the UK officially dropped out of the war, but by March '41, they're de facto at war again with the Axis in Greece.
Of course, if Britain doesn't help Greece, I guess they're screwed, and presumably Yugoslavia survives intact. Though I could be completely ignorant on some factor. Or forgetting something, which I kind of feel like I am. Anyway, interested in your thoughts.