Democracy is when you drop a ballot every two/four years, and the elected officers ignore you while they take millions of donation from wealthy donors. Dictatorship is when the unelected representatives work their ass off to better the lives of the average citizens, because they're afraid of a revolution.

(P.S.: Xi Jin Ping is as unelected as the British Prime Minister, but I don't see people calling the UK a dictatorship.)

The UK PM change happened indirectly as a result of poor performance in the local elections. It does actually matter that the UK has multiple parties that effectively compete, even if some of them are blatantly sockpuppets for overseas millionaires.