My way of thinking is that the £18600 minimum has effectively filtered out many potential applicants from applying in the first place, i.e. earning less than £18600 gross income p.a., unless they can demonstrate that they can make up the shortfall by overtime and bonuses etc.
It hadn't really occurred to me that someone might apply, knowing full well that they cant meet that £18600 requirement, as the fees are such a lot of money to lose.