An Australian told me that, in practice,almost everybody votes though the fine for not doing so is small. My informant didn't say how many turned up but spoiled their ballot papers or the equivalent, or put 'none of the above'.
No, if the apathetic don't vote, presumably they don't care enough to be concerned much either way, perhaps thinking 'they're all the same, those politicians'. That's likely to be the problem. Years ago, Labour and the Tories were far apart. Since Blair was first elected PM that distance has shrunk to almost nothing.