I don't know quite why you have this obsession with Sinclair but consider this.
You met him once briefly, and based on him being 'charming' you've fallen for him. Well, every politician I've met in person (and that's quite a few, including the dread Thatcher) has been 'charming', and if I was to base my assessment of them solely on that no doubt I would be similarly fooled. However in the case of politicians it's easy to come across enough additional information that I can say that all those 'charming' people are in fact scheming, self-serving scumbags of the first order (I note in passing in relation to politicians that "superficial charm" is one of the identifying characteristics of psychopaths.). Charm at an initial meeting is not a good guide to assessing anyone's character, it can mislead, or it can be a trait of a genuinely warm person, but using it as the cornerstone of one's assessment of a person is foolish.
I know two people who worked for Sinclair and their remarks on him (delivered to me in person) are far from complimentary both about him as a person and about his true capabilities; you might want to consider what the effect of being recorded (and subsequently edited) has on what someone will willingly say about another person that they know. One of those two people I had worked and socialised with for over two years before his former employer came up in conversation, so I think I can claim to know him well enough to be able to judge where he was 'coming from'. In fact, he is the kind who tries to find the good in everybody, so I attach particular weight to the fact that he was prepared to be highly critical of his former boss.
To correct the record, I don't have an obsession about Sinclair, he just fascinates me, like it or not, he has left a big technological legacy behind him. Nobody, least of all me, has said that everything he did was ethical, or even done to the best it could be done etc. He got me into electronics from an early age, he also got me involved with computers and got me dabbling a bit with programming on the Spectrum. I seriously doubt that I'm alone in that respect, many programmers today, first cut their teeth with Sinclair machines, not because they were the best, but because they could personally afford them. That right there is perhaps Sinclair's greatest claim to fame, that his products were designed to market at a price point that many more people could enjoy the benefits of owning something that was previously only available to the more affluent people in society.
Also consider this as well, there is the possibility that the person you know might well have parted company with Sinclair under a cloud for some reason if that is the case, is he going to be 100% honest about his relationship with Sinclair, I think not.
I'm also the type of person who tries to see the best in people rather than the worst, but the truth is that each one of us has a nasty side, if provoked enough, that will come to the fore. I was brought up to respect others and to treat people in the same fashion I'd like to be treated myself.