Although I currently am only classed as a "wannabee". Do any of you "Orange" guys not belong to some kind of union? If you do and they are of any worth then surely they will have appointed a shall we say "**** Hot" solicitor who can argue on your behalf especially when some so-called manager tries to make it near impossible for you to leave.
I had a similar situation with a previous employer and if I remember correctly, an employer does not have to give you a reference at all. But what they most certainly cannot do is deliberately/maliciously give you a bad one if it is not warranted.