you know you're british when

I’m sorry but THE LANGUAGE WAS CREATED IN MY COUNTRY!!! That’s why it’s called English.

If I wanted to use far too many z’s and not enough u’s  I would go for “American English” or you know “English - US” as Microsoft use. 

English is from England and so “British English” as you put it should be, by default, “English”.

Okay rant over.