It’s a recording of the defunct “Richard & Judy” UK TV show.
so the hum could actually be on the (video ?) cassette recording of the TV show,
If that’s the case then your only hope is a de-hum plugin for Audacity e.g. …
https://forum.audacityteam.org/t/buzzing-noise-in-the-background/13559/15 [Steve’s]
https://forum.audacityteam.org/t/multiple-notches-with-nyquist-prompt/7583/10 [mine]
Both plugins both remove mains* hum but they add an echoey effect.
[* if it’s UK TV its 50Hz fundamental]