Big Finish (in-universe)

Big Finish was an organisation whose logo included their name in white text over a red background. (WC: The Zygon Isolation) They had several "loyal listeners". (WC: )

History
Big Finish once gave Christmas presents to Captain Jack Harkness, Number 6, John Steed, Emma Peel, Jago, Litefoot, Doctor Ninestein, the Fourth Doctor, and their "loyal listeners". (WC: )

By 10 May 2020, Petronella Osgood had an icon labelled "Big Finish" on her computer. (WC: )

In non-valid sources
According to the Doctor's Five Hundred Year Diary, Big Finish was the "most successful creator to come out of Mutter's Spiral" - they were an Earth based production company associated with BBC's Doctor Who, and in 2021, they released the previously unproduced 1978 serial The Doomsday Contract by John Lloyd and Nev Fountain, starring Tom Baker, Lalla Ward, John Leeson, and Julian Wadham. (WC: )

Other matters
In the real world, Big Finish is a company that has produced Doctor Who audio stories, as well as several spin-offs, since 1998.

Big Finish (The Zygon Isolation)