Time limit for claiming unfair dismissal compensation
There is a strict time limit for claiming unfair dismissal compensation. It's important to act quickly so you don’t miss your chance to claim.
How long do you have to claim?
The time limit for claiming unfair dismissal compensation should be adhered to. Unfair dismissal applications to an Employment Tribunal should normally be made as soon as the employer has given notice of dismissal and should be received within the period of three months beginning with the employee's effective date of termination.

If the employer's disciplinary appeal process is taking a long time you must still issue an Employment Tribunal claim within the three month time limit. Therefore you do not need to wait for the outcome from the internal appeal process.
If the application is received any later than that date the Tribunal will consider the complaint only if they believe it was not reasonably practicable for the employee to have made the complaint within the three-month period and that it has been made within such further period as they consider reasonable.
Unfortunately the time limit is very strict so we would be unable to help you