You qualify to bring an Unfair Dismissal claim against your employers in the Regional Employment Tribunal as you have over two years’ continuous service.
Regardless of their reasons for your dismissal, your employers should have followed a fair investigation and disciplinary process before deciding to dismiss you. You should also have been given the right to appeal the dismissal.
It appears to me that your employers have an arguable case that if you are guilty of fraud or theft from the company, they may dismiss you for gross misconduct with paying your notice pay or other contractual and statutory entitlements.
You have three months from the date of dismissal to lodge an ET1 Claim Form with the Central Tribunal Office. This is a very strict and very short time limit, so if you want to bring a claim, I strongly recommend that you act immediately.
You must notify the government's employment Advice Conciliation and Arbitration Service (ACAS) to commence their Early Conciliation Process (ECP), which is mandatory. The ACAS ECP will “freeze” the three-month limitation deadline to issue Tribunal proceedings. During the ECP, ACAS will attempt to facilitate a Settlement Agreement between you and your employers.
You should seek payment of your Notice Pay, Accrued Holiday Pay, and other outstanding benefits and an additional Termination Payment to reflect you winning the Basic and Compensatory Awards at Tribunal as well as a factual and impartial reference to future employers.