To be that far and/or long away from it I suspect they call it 'home'.

I never heard the expression Britain used to not mean Ireland as well as the rest, and assume it to be a cultural rather than political tag.
But I could be mistaken. Besides despite what some think, Penny is absolutely right, the term began to be used off shore in the European mainland to describe the place. I do not think they knew or cared to separate one island off from the rest; indeed, if they did I would be really interested to know why.