there was certainly a much more interesting programme in there struggling to get out, more relevant to our current preoccupations.
What Mangold discussed were attempts by various parts of the establishment to expose/smear the sexual activities of a leading politician while other parts, including the security services, closed ranks behind a member of the Privy Council. These events, with backstory of sexual, and in particular illegally homosexual, scandals and blackmail, and the stark warning from Denning were a very few years, and a change of government, before the Elm Guest house, Dickens dossier and so on. So while those attempts at exposure may well have stemmed from sexual prurience or party advantage, there was also a well founded 'national security' element. And then Thorpe nearly became Home Secretary which Mangold, along with all the other reports I've so far encountered, dismissed with a one-line "the rest of the Libs wouldn't be doing with that".
Those elements frame the story, not a shot dog or a (funny but) bigot like Waugh.