first theres no reason why british refuges would take on citenzenship in canada or austrailia (especially australia, as they wouldnt remove the restrictions on immigration for anything)....its mor likly theyd retain british citezenship but probaly get dual status in commmonwealth countries
second....theres no reason for a federation as ai pointed out in the map...people would still recognize it all under uk domain (especially as its backed by nato forces and americans, who would see no reason to aid a federation out of the blue, and i could guess that the royal anvy and army wouldnt support it either)
Thanks for the pointers, never really thought about that, silly me lol