A critical point you just made about the raiders slipping out into the Atlantic. By 45 even if there is no war both radar and arial survalance are going to make it much more difficult for a raider to break into the Atlantic and to remain undetected there. A hand full of light carriers for instance could keep the convoy lanes across the Atlantic pretty well covered as long as conditions permitted flying. Likewise the picket line across the access route North of Britain could be much more efficient. Few ships had radar in 1940 by 1945 even PT boats were equipped with it. Not sure if we should be addressing it but there's also a chance the Nazi government doesn't survive into 45 or later. I can see this falling out several ways.