Take a look on this google translate of time line of PPoU

https://www-ceskatelevize-cz.translate.goog/porady/1027405251-the-plastic-people-of-the-universe/20032828009/11223-casova-osa/?_x_tr_sl=cs&_x_tr_tl=en&_x_tr_hl=cs&_x_tr_pto=wapp

Anyway, look for documentary from 2001 called "The Plastic People of the Universe"
https://trakt.tv/movies/the-plastic-people-of-the-universe-2001