So, it seems that former National MP and cabinet minister Richard Worth will escape prosecution. The police have concluded that there isn't enough evidence to bring a prosecution, and as a result the victim has dropped her complaint. The former sadly isn't that surprising - sex cases are notoriously hard to prosecute, as by their nature there tend to be no other witnesses, so it comes down to a credibility contest between the victim and alleged offender in which the latter has the advantage of being able to put the former on trial. Mucking about with offence and conviction statistics, it seems that only half of sexual assault cases are "resolved" (meaning an alleged offender is identified - this roughly translates into the number of prosecutions), and only a third of those brought to trial result in conviction (the average for murder is over half, and manslaughter around two thirds). And that's without even getting into what proportion of such crimes are ever reported. Basically, if Worth did do anything, the odds were in favour of him getting away with it.
But while he may have escaped legal sanction, the behaviour alleged is sufficiently dubious that no-one in their right mind would want that smell around their cabinet table - or in their party (political or otherwise). That is apparently some consolation to the victim, but its politics, not justice.