Depending on the episode, Red Dawrf has either the American or British gestures.
E.g. In Bodyswap, Rimmer (as Lister) displays the “Double British”, but in Back to Reality Kryten (as Jake Bullet) talks about people parking themselves on “this mid digit”. In DNA (I think), Lister gives the single finger to the Vindaloo monster. Once a scutter did the British “V” to Rimmer
All very exciting to non-fans of Red Dwarf, but there you go. 
There’s also “The Shocker .” The thumb holds the ring finger curled to the palm and the other fingers are extended. The index and middle finger are touching. The hand is held back side away from the gesturer. “Two in the pink, one in the stink.”
Things I learned on the Dope, which I would have never guessed before, nr. 312: Flipping/Showing the bird to an American (apparently, even a police officer?) is not automatically an insult (and therefore, not automatically a fine from a cop).
I don’t think I can agree at all with your conclusion. I.e., if you flip somebody the bird, it is at minimum extremely rude, and at maximum, would get you severely beaten. And possibly arrested if directed at a cop.
Did you think I was talking about flipping the bird, constanze? I was not. I was talking about tapping the forehead (in my mind, canonically, two quick taps on the side, with the forefinger and the middle finger together), an entirely different gesture.
Two from here in Japan:
Making a fist with the thumb between the index and middle fingers a la the old “I’ve got your nose joke” means sex.
Pulling down the lower eyelid with the index finger, while sticking out the tounge is the (somewhat childish) equivilant of thumbing ones nose, and is known as akanbe (The tounge bit often comes at the end of actually saying “akanbe”, stressing the “e”.)