In fairness, either City didn’t challenge the evidence effectively, thought it futile to challenge or the Tribunal rejected City’s arguments on the reality of RPTs. If City had made material submissions on the point, I suspect we’d have seen them in the judgment so, most likely, we tactically decided to fight other battles especially as it sounds like there were no documents disclosed on the topic before 2021.
In reality, it seems to me that it couldn’t be said to be that hard to challenge a designation of a RPT given that UEFA did exactly that in 2014 (assuming the press was true that it concluded both Etihad and Etisalat were actually RPTs
"In 2014 Uefa’s consultants, reported to be PwC, are understood to have advised the CFCB that Aabar and Etisalat were “related parties” to City because Mansour was the chairman of the investment funds which owned them. After further research Uefa was also advised that Etihad should be considered a related sponsor because of relationships of Mansour’s with members of the extended ruling family involved in the airline." https://www.theguardian.com/footbal...accounting-sponsorships-uefa-champions-league) - although it didn’t bother in 2020.
City couldn’t make that submission however without bringing focus to UEFAs conclusion that City’s accounts were wrong on that point.