Employees are entitled to appeal against any gross misconduct dismissal. If an employee does decide to appeal against a decision, the basis can be due to:
The way the disciplinary action was taken against them.
The evidence on which the employer has based a decision.
E.g. if an employer thought something was true without having evidence or doesn't have enough evidence to support it.
The actual decision the employer made.
E.g. if they have acted differently in the past in similar disciplinaries and the action they're proposing is too harsh.
Provide new evidence or reasons why disciplinary action shouldn't be taken.
E.g. an employee has a clean disciplinary record, work record and length of service. It may be that the employee requires training or adjustments to avoid the problem happening again.