I guess without the pressure from the uboats in WW2, and TTL's tripolar world, there's no NATO SOSUS system, and so the UK better be investing in their ASW to be able to hold off the Soviets and all of their boats. From this map, I'd imagine that Norway and Sweden lean heavily towards the Syndicalist bloc, because the Soviets seem like they'd be demanding everything they did without the chastisement of Barbarossa, which might make the Sovs far less willing to back off. If they're under pressure, the Danes and their territories could lead to the GIUK-portion of the SOSUS arrangement, but now you have a complication: the US' block is the Central Powers, and to get to them, you have to get past both the Soviet Navy coming down through the North Sea and then past the (Artist Formerly Known as the Royal Navy)...
That support means essentially a fight all the way into Germany, and that's just a replay of the First World War... it just wouldn't work long-term. I'm amazed the Soviets didn't see that and try and pull their relatives in the Eurosyn into their fight against the Capitalists, because that would cause the ECZ to fail spectacularly. Short of American nukes being based in Germany and releasable to their command in a crisis, I doubt that the ECZ can actually hold their borders against either side.