Mehdismummy,
Not sure if Flowerybeanbag is around. She normally has lots of good advice on this stuff. I sometimes come on too. You might want to post this in employment too so that she sees it.
First things first. Have you worked there at least a year? This is going to sound incredibly harsh, but if the answer is no you have bugger all rights I'm afraid. There are some carve outs (e.g. you can still sue for discrimination and you can still sue for your notice period if you are sacked for gross misconduct and should have been dismissed on notice), but broadly you have no rights.
Hopefully you've been there more than a year. Now you need to focus on this disciplinary hearing...
In terms of the disciplinary, I actually disagree with others. I DO think that it is relevant how others have behaved. This is because a disciplinary decisions needs to be taken in an even handed way. If other people have committed the same 'offence' and no action has been taken, and you are dismissed, it might make the dismissal unfair. I agree with others who have said that I am afraid that they could decide to take a hard line and fire you, but I think it's more difficult for them to do that if they don't treat others the same way.
You need to get your own thoughts clear in your head and you need to present them as succintly (sp?) as possible. I think that your key points are:
- You made an innocent mistake. You put the note in your pocket to change it and forgot. You confessed as soon as you realised.
- You had never been trained on cash control procedure so, although you broke it, you didn't know you were doing so. Explain that you were told you would be trained when you came back from maternity leave, but you weren't. You therefore did not know that you were meant to leave a note.
- That you think it is unfair for you to be singled out for breaching the policy when others have, to your knowledge, done the same. Explain the incident with the manager taking the money. Say that you don't see how it's fair that you are disciplined for an honest mistake and he is not for deliberately borrowing the money (that's what happened, isn't it?).
- Explain your personal circumstances and the stress you are under. Explain that you believe that this may have led to you making the stupid mistake in the first place. If you want to talk about your doctor wanting to sign you off but your manager being angry, then do.
- IF you want to get into it, explain the worry that the manager is against you since you made a complaint about him. Beware though, if the manager is good and they want to keep him, then if you two can't work with one another, it's the junior people who are more likely to take the chop. One reason I might go into this is to strengthen your case for a transfer. Ultimately, it's a bit of a personal choice whether you raise this.
More practically, have you had a letter inviting you to the disciplinary hearing yet? It should explain the charges against you and you have the right to bring a colleague (or, if you happen to know one, a trade union rep even if your workplace is not unionised) with you to the hearing. The moral support can be useful, especially if you get upset...
Hope it goes well. Fingers crossed for you.