Culture clash, of course, is the well-worn theme of this one. Of course it may be necessary to contextualise this in the milieu of the 1970s, the age when everything modern was wonderful, & yet the decade was marked by some incredibale conflcit, the oil crisis has a good go at putting the kibosh on the consumption of the modern era.
It's actually rather difficult to know where to begin on the wealth of culture clashes featured in this episode, with characteristic differences of opinion between Lottie & Hawksworth woven in for good measure. President Baras, of course references Che Guevara, who had died by execution five years before this episode. He is played superlatively by Mike Pratt, of Randall and Hopkirk (Deceased) fame: a truly versatile actor. Baras is not merely the popular folk hero figure but is also - on the surface - the representative of modernity in his nation, while it becomes apparent he is not averse to the old ways. As a side note Pratt is only in his early forties here but looks older, as people often do in these old TV programmes, because of all the smoking & package holidays to the sun. Pratt died of lung cancer only four years after this.
I like Hawksworth's chatting up of President Baras's sister a lot. He comes across almost as an awkward schoolboy in this episode - he has been pictured driving a vintage Lagonda earlier in the series but his blokey preoccupation with buying rare parts at auction becomes apparent here. Of course it could partly be mischief on Lottie's part that she gives Hawksworth the sister to deal with, to his embarrassment, but his uncomfortable reaction to her, actually running away from her at one point, adds to the ungainly schoolboy impression.
His clash with Lottie, of course, is that Baras is an old flame of hers, so Lottie also appears in a slightly different light.
If I have a criticism of this one it would be that the magical ritual depicted at the beginning starts a thread of the story which is not picked up again until part 3, when Baras mentions Vodou in the exhibition & you remember it. The reason this is unfortunate is this is actually the thread which explains the story & makes it hang together - it comes together when Lottie comments after the scene in the cemetery that Baras is a fatalist in his blood. The whole point here is the sense of helplessness in the face of ancient magical power: 'We simply haven't a clue, have we, tiger?', Lottie says.
Given this helplessness, I like the simplicity of the ending & lack of a showdown, a lot. It provides a neat side-step to avoid directly confronting occult powers. The unexpected arrest at the end also neatly distracts from the fact that a showdown has been avoided, & President Baras is the good guy, & of course the victim.
Ultimately here the magic both holds the tale together & is a complete red herring. Apart from that that thread was neglected in the middle of the episode, it is otherwise tightly plotted & a gripping Spyder's Web episode.