I agree that middle lane hoggers are very annoying. I have to say that the way they treat this in the USA works well. There, on a multi-lane highway, you simply choose the lane you want to be in, and stay there. You pass and are passed by traffic on both sides. Because everybody knows this, it works fine. Here, it wouldn't because we're just not expecting to be passed on the nearside so are probably not keeping a proper look-out. What isn't tolerated there, if spotted by the cops, is weaving from lane to lane to overtake. Incidentally here, passing on the nearside (undertaking), isn't an offence in itself but can often be classed as DWDCA.