Thanks, Frank, for this interesting piece about a series I only vaguely knew of, until now. (I must admit that I only skimmed the last portion of your in-depth review because I have just acquired a copy of the complete series on the strength of this and so wanted to avoid 'spoilers'...)
I once had a chat with Mike Hodges at a 'Shots in the Dark' crime film festival at Nottigham's Broadway arts centre. Must've been 1998/99 as it was after he'd introduced a pre-release screening of his film CROUPIER, which I remember enjoying.
Anyway, just dove into the first episode of THE TYRANT KING - nostalgia a-go-go for those of a certain age... and you're not wrong about the prominent prog soundtrack!
Cheers.