military law

my fiance was sentenced to two years in the military corrective training
unit in Colchester, Essex. he has now served half his sentence but wants to
know if there is anyway he can appeal this.
the evidence the prosecution said they had was returned to me last week.
during his court martial he was not allowed to see this evidence. (clothing
he was wearing when he was fighting with another chef in the army who
incurred a cut to his hand). his solicitors were told that the clothig was
covered in blood and that if he pleaded not guilty and it went to trial then
this would be used as evidence and he would get a greater sentence. when i
received the clothes there is only one spot of blood on them the size of a
5p piece. my fiance is very upset to the point of feeling suicidal as he
could not remember much from the night as he has problems with his memory
due to a head injury incurred a few years ago. is there anyway this can be
appealed even though his sentence was passed 27/07/07?