[Iceni]

The British Isles are made up of many Isles, so yes they would be part of what ever British Nation they are part of now.

As for our old colonies, I suspect they would want to keep a close affiliation after they had got used to our new Nationalist Government. It would be very hard to lose the close affiliation we have with our brethren in the new world as most families in our Isles have family in these lands.