There is more to the "King's English" than just grammar. It also includes pronunciation and diction.
If I speak "King's English," using the proper grammar but with an American or Australian accent and/or pronunciation, am I really speaking the "King's English?"
WRT the phrase in question as published, it is more likely British slang than proper "King's English" grammar.
“There is more to the ‘King’s English’ than just grammar.”
Of course, but the discussion I was involved in with another FReeper was SPECIFIC only to grammar and syntax.
That’s like saying, when the topic is power steering, “There is more to a car than power steering”.