I have written often about how feedback helps students. It does not always happen though. Diagnostic marking can be time consuming and, without a culture of value for it, can have a blunt effect.
In the face of this, there are some places where you can apparently have your essays marked from an external source. I still remember having an essay marked by a tutor and university, and receiving very little in the way of criteria-based feedback. Upon trying to analyse my essay, I was greeted with the notion that I wanted “Truth with a capital T”. Maybe so: I was paying for such challenge, even if that is not what was meant.
This interesting post suggests that there are options for students who are not receiving the marking they desire: http://www.thestudentroom.co.uk/showthread.php?t=2215504