[lookoutwales]

Which ITV company had the best opt out studio or location, in each of the three of them?

I doubt you can really answer that question.

There's not a huge amount of Telethon clips online from every region (speaking personally, I was too young to remember it) and its legacy, as documented elsewhere, is somewhat tainted to the point that some within ITV came to disown it in hindsight.

AFAIK, only one or two regions have featured it in their anniversary retrospectives in later years - HTV Wales for one (not including those sound problems in 1990)

That said, as someone pointed out in the YT comments for the Bob the Fish film, the charity purpose may have been better served and appreciated in smaller regions far more closely connected with their audience than the Big 5, for instance. Take TSW (to the point they announced their final total for 1992 in the dying seconds of their franchise)