My theory about V (in the graphic novel) is that
spoiler
V and Evie are the same person. Evie is a trans woman who was imprisoned in cell five for being "undesirable", like the lesbian woman in the cell next to her. The chapter where Evie is "tortured" by V is actually her V persona making Evie face the fact that this actually happened to her. The bad guys say "you're the man from cell five" because they are bigots who refuse to accept her as female.
Sexual liberation and autonomy is a big part of V for Vendetta. I'm probably wrong about my theory but I just think it fits the rest of the message of the graphic novel.