I think that is very polite and customer friendly. If you are right about the reasons, you could actually back up his reinstatement application with one of your own under Rule 17(4)(b), although I think the reason why that subparagraph is there is when you have withdrawn your own case, but I think the language stretches to a respondent applying for an appeal to be reinstated.
Your courteous gesture deserves the following reply: “No thanks, I don’t want to pursue it. When I read your clear and impartial submission I immediately understood that the decision was correct, and my appeal could not succeed. it’s nice to have it explained so well”.
