:::Your link is not to the Queen's "Canadian website", but to a website run by the Canadian government.  It in turn links to Royal Style and Titles Act R.S.C., 1985, c. R-12, which btw has the force of law in Canada and says, "The assent of the Parliament of Canada is hereby given to...the following Royal Style and Titles, namely: Elizabeth the Second...of the United Kingdom, Canada and Her other Realms and Territories Queen."  The "British website" otoh is "the official web site of the British Monarchy. Written and managed by the Royal Household at Buckingham Palace, the site aims to provide an authoritative resource of information about the Monarchy and Royal Family, past and present."  Whether or not the site is "UK centric" is irrelevant - that is how the world knows her.