Green, white and orange, as a flag of Great Britain? I think the Irish might have something to say about that!! The Republic of Ireland is part of the British Isles (which is a geographic reference, not political), Great Britain is the main island of the British Isles that comprises England, Scotland and Wales. A very important distinction.

Which is why it states on the cover of the UK Passport, "The United Kingdom of Great Britain AND Northern Ireland". Interestingly this excluded the multitudes of islands that make up the UK.

As said before - tweak your explanation to the answer for flags. You are likely to cause huge offense there! You could use British isles, teams that complete in the 6 nations?

Also complementary colours are also opposites