Audio problem: When the high Lister plays the harp, his fingers are out of sync to what is being played. (00:11:30)
Audio problem: When the high Kryten picks up the bomb, the high Cat can be seen to start speaking but no sound is heard. In the next shot, the high Cat is then smiling. (00:13:30)
Answer: It's Queen Victoria, someone any Englishman would recognize, and needed no introduction.