Hi
I have not read this whole thread but will just add, if your university has an official appeals route take it. See a lawyer at university or students union for advice in preparing the case.
I hope you have a very strong case because the universities rarely amend grades.
I should just warn you that the rules that govern universities are stipulated by the OIA. If you don't win the case at university, to be honest you wont unless you have an extraordinarily case and can prove this( which wont matter because most instances will fall under academic judgement) you can appeal to the OIA. But its almost impossible to prove, the universities have something in place which protects them from students and other academic staff questions their judgement. So your buggered to begin with, because you cant questions academic judgement specially in regards to marking exams and coursework, Some university recognise this stupidity in the law and actually will allow a remark of assignment and others not. Its an extremely unfair system that provides lecturers with every opportunity to jump through giant holes in the law and mess up your life.
success at university and good grades are very easy
1) work hard
2) suck up to teachers, ask for help when stuck
3) don't ever question anything, they can ruin your life and you can do very little
this comes from experience in helping someone with their case, lets say it
was bordering on criminal what they did and proof was all there but was thrown out under "questioning academic judgement", we are still in shocked till this day

Even if you win the appeals case with the OIA your university can overturn the decision as its
not legally biding decision, they have only an advisory role in this matter.
the courts in the UK also follow a similar line and will throw your case away if you ever decided to fight it in court.
OIA website
http://www.oiahe.org.uk/
good luck