no every one just asked for holiday and it gets written in the diary. but because I wrote in the diary the am has made it look like I wrote it, not told anyone in the hope that everyone thinks I booked it off and they have forgotten. I wouldn't be bothered to go though all this trouble for a days wage I would have just called in sick.It's OP's word against the AM's though. Technically if his contract states that he must fill out a holiday form, then that's what you must do.
OP, did you not ask the AM or GM for a holiday form? Do they not have to sign the diary to say they've authorised the leave?
Bottom line it does sound petty, and these are probably things you should bring up if you have a hearing.