“Grand Choulaa” - this looks to me like the locals taking the piss.
Initially Macartney did not realize that he was supposed to prostrate himself before the emperor. Nor, when it was explained to him, was he willing to do so. Despite his great admiration for the prosperity and civilization of the Qing Empire, he viewed Qianlong as an equal to the king of England
Macartney would never have really considered Quianlong as equal to the King of Britain (England and Scotland became Britain a little earlier). I am also sure that Quianlong's people would have had exactly the same notion in reverse for exactly the same reason.