Revealing mistake: At The End of the episode when Ace takes off in the ejector seat, a black cable can be seen lifting the chair up. (00:27:55)
Revealing mistake: When Lister types Starbug's co-ordinates for the distress call, Lister's fingers do not touch the keyboard. (00:03:00)
Revealing mistake: When Kryten's head explodes, you can tell the head is a dummy. (00:08:05)
Revealing mistake: When Kochanski is on the phone falling through space, her lips do not match what she is saying. (00:25:55)
Revealing mistake: When Lister kicks the simulant in the head, you can see he misses him by about a foot. (00:20:00)
Revealing mistake: When Ace accelerates away from the Nazi troops, he is holding a gun in his right hand. He should not have been able to accelerate away as the throttle handle is on the right. (00:03:45)
Revealing mistake: When Able screws on Kryten's head he only turns it once, yet in Tikka To Ride, Lister screws his head on at least twice around. (00:15:30)
Revealing mistake: After the crew transport themselves out of the book depository to escape the FBI, the astronaut helmet is transported afterwards and the two FBI agents start shooting at the box the helmet was placed on. When the box is shot, there are no bullet holes left on it.
Revealing mistake: When the simulant hits Able over the head with the steel bar, you can clearly see it bend. He hits him a second time a few moments later and it is straight again. (00:14:45)
Revealing mistake: When Kochanski is shot with the spear, the padding that gives the impression the spear is through her leg is visibly bulging in her trousers as ahe pulls on the rope. (00:26:50)
Revealing mistake: When the ship crashes into the snow planet, a wire can be seen attached to it as it crashes.
Revealing mistake: When Lee Harvey Oswald is preparing to shoot JFK on the fifth floor of the book depository, there is a shot of him from the side where he points his gun out of the window. To his left are a numerous boxes belonging to the book depository. Many of the boxes have "books" written on them, and some have hand written numbers on them. Later in the episode, the crew go back in time to send Oswald up to the sixth floor, but in the side view shot where he points his gun out of the window this time, the boxes are completely identical to the ones used on the fifth floor. The same set was likely reused.
Answer: It's Queen Victoria, someone any Englishman would recognize, and needed no introduction.