ESA and Tribunal decisions

I have a query, which to me seems obvious but i have that familiar niggly voice nagging me in the background and i just want some thoughts on procedure.

I have just had a client who was placed in the WRAG of ESA last July. He rang JC+ to ask for appeal advice and was told he could appeal by writing to them, but appeals can take 9 months to resolve.
He wrote to them in July asking for a reconsideration, and as he heard nothing he called them to be told (yep=you guessed) they had not got the letter.

They posted him a GL24 and he came in to see me for assistance. I read his decision letter from July and it appears he was put in the WRAG following a tribunal.

I told him we wouldnt be able to appeal, as the determination had already been made by tribunal back then, and a new tribunal has no authority to overrule an earlier one (apart from error in law etc)

I said we could apply for a supersession but he said there had been no deterioration in health, and he simply got the wrong decision in the first place.
I told him he may not be able to appeal as Tribunal has spoken, but he countered by saying his decision letter quite clearly states he has the right of appeal (which it does) and therefore wants to appeal on that basis. He also states he called JC+ twice, and was told on both occasions he could appeal, and they even posted him his GL24.

Any thoughts??

I would help them appeal, and just assume that the Tribunal hadn’t made a decision on whether any of the Schedule 3 descriptors applied.

From memory, part of the standard appeal bundle text is a request for the tribunal to consider schedule 3, but if they can’t make a decision, then the tribunal should return this for a decision maker to decide

Supersession is available if you think the tribunal’s decision was made in ignorance of, or as a mistake to, a material fact.