In the attempt to satisfy Austria at the time, Britain gave their electoral vote in Hanover for the candidacy of Maria Theresa's son, Joseph, as the Holy Roman Emperor, much to the dismay of Frederick and Prussia. Not only that, Britain would soon join the Austro-Russian alliance, but complications arose. Britain's basic framework for the alliance itself was to protect Hanover's interests against France. While at the same time, Kaunitz kept approaching the French in the hope of establishing such alliance with Austria. Not only that, France had no intention to ally with Russia, who meddled with their affairs in Austria's succession war, years earlier, and saw the complete dismemberment of Prussia as unacceptable to the stability of Central Europe.
What country and person were displeased that Britain used it Hanover vote to elect Joseph as the Holy Roman Emporer?
Frederick and Prussia