[noggin]

I don't understand what you're suggesting?  Unless I'm very wrong (@wesk05) I thought Player-led vs TV-led was the route the DV metadata took from source to sink (and the processing based on this metadata was carried out in the display irrespective of this).  I thought the difference was whether the DV metadata (which I think is derived from the RPU?) was either carried over HDMI using now-standard protocols, where previously the DV metadata had to be tunnelled within the active HDMI video (and detected and 'un tunnelled' in the display)

Is this not the case - is the Player-led vs Display-led instead to do with how the BL+EL+RPU stuff is processed either in the player or the TV ?

From a purely technical stand point, there shouldn't be any difference between player-led vs TV-led modes for profile 7 media on Ultra-HD Blu-ray players. User reports (like that of @DaMacFunkin) suggest that this is not always the case. You may occasionally see noticeable difference between player-led and TV-led modes in certain scenes. One likely explanation for this is subtle differences in ST2084 EOTF application in the two modes.

Should the baseband video output of the UHD BD player over the HDMI connection in both player-led and TV-led modes be the same (give or take possibly noise due to tunnelling?) - with the metadata path being the only difference, or does the player do a lot more processing based on metadata in one model than the other?