Not Churchill. Someone else as Prime minister, Halifax or any other. But asking this question about Winston Churchill is the same as asking "what if Winston Churchill was not Winston Churchill ?".
Churchill was not only a name. He was a man whose whole life was characterized by irrevocable commitments that made that he was finally chosen as Prime minister at the worst moment of the war because he was uncompromising. He really meant "we shall never surrender".
From what I have read, this seems true, but he is a politician.
If he sees the mood is for peace, he might accept it to prepare for round 2.
Otherwise, I think not having Churchill elected or dead is needed for the pod. Interesting that working German torpedoes takes care of removing Churchill and the increase success against the British at the same time.