If Japan don’t attack in the frist round, I think of moving the uk battleship to Queensland in uk1, and also station the ANZAC sub, dd and US dd from Phillippines there. This should greatly enhance your possibilities to save the most valuable asset in the british fleet.
But how does a Japanese attack on a seazone containing both uk, anzac and us units work? Can they choose to say just attack the battleship, the attack will of course bring them to war with us and anzac too, but can they choose to only target the british battleship in this attack since all the units are in a neutral state as the attack happens?
One more thing:
Will a british warship block the move of a japanese assualt on an island when the japanese must move through the seazone containing the british ship (japanese two sea zones away from the island, british warship one sea zone away), or will the state of war first commence when the japanese actually land on the island?