Additional to the first post, as I am not in Britain I am unable to answer on their behalf re the finals call question. However, I would venture to say that if you keep a good listen out on the radio, the 'finals' call will always be accompanied by a runway number. That should help to diffuse your confusion.
Why it is stated as a plural, I have no idea, I guess its because the English language has many variations and it just so happens that the English are the worst at speaking it correctly.
Hang on a mo.... I say 'finals' too! Perhaps its the Canadians who have it wrong!
