@jbuckbuddy You should always use ANZAC under a different color than UK and the reason why I say this is because if ANZAC and UK attack, as long as an ANZAC unit is present, you can give that territory to ANZAC instead of UK if you wish to of course.
Plus you should keep the colors different so you can see force projection by ANZAC. If ANZAC surrenders before UK, you need to know what units are going off the board.