Thanks again @Plex . Turns out this is a known issue: Is Anyone's Plex Live TV/DVR Function Working?
I’ve wasted hours on this, you could have at least put a link to the known issue here: https://support.plex.tv/articles/225877347-live-tv-dvr/ or https://support.plex.tv/articles/using-an-xmltv-guide/
Very unimpressed. Kudos to @SE56 for trying to help. Severely negative kudos to @Plex for very poor forum management (I’m a paid up plex pass user asking for help) and for not making it known there is an issue and most of all for wasting hours of my time.