Many thanks for your patience. If you have been continuously employed at your place of work for less than 2 years then your employment rights will unfortunately be somewhat limited. Most importantly, you will not be protected against unfair dismissal. This means that your employer can dismiss you for more or less any reason, and without following a fair procedure, as long as their decision is not based on discriminatory grounds (i.e. because of gender, race, religion, age, a disability, sexual orientation, etc.) or because you were trying to assert any of your statutory rights (e.g. requesting maternity/paternity leave, etc.). So what you have been advised is true I'm afraid – if they want to dismiss they can even if you have done absolutely nothing wrong or you have a defence for what happened.
If you wanted to resign then you would be expected to serve and work your notice period, otherwise you would be acting in breach of contract. However, in that time the employer could still proceed with the disciplinary and dismiss you. If you were to leave without giving the notice period required of you the employer can still mention in a reference that you left in breach of contract pending a disciplinary hearing. Whilst not as bad as a dismissal, employers can draw some inferences from this.
I would say in the circumstances it is best if you try to negotiate a mutually agreeable exit where they agree to let you go and drop the disciplinary against you. If they do not and you are either dismissed or have to leave, then your only rights will be in relation to the references you get from them and there are certain legal principles they have to adhere to and which you can potentially challenge if the contents are misleading.
This is your basic legal position. I have more detailed advice for you in terms of the references they provide about you, which I wish to discuss so please take a second to leave a positive rating for the service so far (by selecting 3, 4 or 5 stars) and I can continue with that and answer any further questions you may have. Don’t worry, there is no extra cost and leaving a rating will not close the question and we can continue this discussion. Thank you