Great Britain is in fact England, Scotland and Wales.
The British Isles or the United Kingdom is England, Scotland, Wales,
Northern Ireland and various islands including the Channel Islands, the
Isle of Man, the Scilly Isles and the Scottish Islands (part of Scotland)
For the purposes of the Olympic Games and the World Championships the
representative team is from the United Kingdom.
For the Commonwealth Games England, Scotland, Wales, the Isle of Man and
the Channel Islands send their own representative teams.
I am not sure how European Championships work. Can anyone elaborate on