Continuity mistake: At the start of the episode, it is clear that the capsule fully rotates and the "contents: 2" sign is not on the capsule. (00:01:05)
Continuity mistake: At the start of the episode when we first see the polymorph, it looks into the mirror, then covers its eyes. Yet when we see the reflection, it already has its hands over its eyes before it gets to the mirror. (00:01:30)
Continuity mistake: When the Polymorph is switching between various appearances at the start, it stops at a rabbit. When the Polymorph stops at the rabbit, there is a damp stain beside the two yellow lines on the floor. This damp stain was not there when the Polymorph was switching between other forms. The stain just suddenly appears out of nowhere. (00:01:45)
Continuity mistake: Kryten removes the polymorph underpants and throws them under the covers of Lister's bed. When he checks the bed and pulls out a snake the pants are now on top of the covers (even though he says they're gone) and the covers themselves are now arranged differently. (00:10:00)
Continuity mistake: When the group are about to open the door with the heat seeking missiles inside and the Polymorph sneaks up behind them, Lister is standing at the front of the group, Cat and Kryten are behind Lister and Rimmer is standing at the back, behind all three. In the next shot, as the missiles exit the door, Rimmer is now suddenly standing front of Cat. (00:24:40)
Answer: It's Queen Victoria, someone any Englishman would recognize, and needed no introduction.