This is highly unusual!
Normally the appeal is the property of the appellent and as such is your property to submit or withdraw. Does your company procedure mention anything about this? If you are a Union member have you sought their advice?
Of course the reason the company might be refusing to allow you to withdraw is because at appeal, companies can impose a tougher sanction as well as a lesser one. Being 1 step away from
dismissal I think you can see where this might be heading if someoe higher up wants you out!
I know that if you give notice and then change your mind, companies don't have to accept a retraction and maybe this is similar?
I'm sure others will advise. I'm also unsure how an ET would view it. Personnaly I would fight my case if I thought the sanction was harsh or if I believed I had done nothing wrong.
Regards,
Paul.