Just echoing what Dan wrote, this sounds interesting but slightly preposterous in the extent to which you push it... I just instinctively don’t trust the extent to which you are pushing the argument (no sendage).
First up I'm not claiming to be some expert on grime, this is just my 2c worth. I've never been into it on the level of individual artists & producers, so my take on it is macro.
I was at LSBU for two years with a lot of young guys from African backgrounds,and the music they listened to (and made themselves in a lot of cases) was in some hinterland between RnB, grime, bashment and hiplife, without being easliy characterisable as any of those. That got me thinking of grime in terms of a UK outpost of some international west African youth music.
Then I went to Ghana in the summer just gone, and I was hearing a lot of hiplife on the street that was darker and more aggressive than the hiplife you come across in the UK. From speaking to Ghanains who were into it, it seems this stuff is way underground because the money men won't go near anything with that nihilistic tone - hence most hiplife that gets released is sunny and romantic, and where it is political it's very earnest and conscious. So there's a kind of self-censorship going on, and the problems the underground hiplife artists have (misunderstood by the music industry, fear of compromise, trying to make money from a genre where the big fans won't or don't buy music) are similar to the problems the grime scene has in the UK.
This blog has some great info on the Ghanain music industry from someone who spent a lot longer there than I did.
Apparently they have big yard dances playing everything across the hiplife-ragga-RnB spectrum, but they don't seem to be into taping them. I tried to get tapes a few times but didn't have any joy

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And what about the clear evolution of grime from a genre so British it’s country of origin was contained in it’s name – UKG? How do PAUG and So Solid fit into your idea, they were clearing pushing the vocal side of (the admittedly hybrid genre) garage. At what point did the West African influence come in?
I think the idea that grime evolved directly from UK garage is an orthodoxy worth challenging - which isn't to say that it didn't, just that people seem to say it without qualification. There's very little musical link between grime and UKG - to someone coming at it fresh, grime sounds much more like hiplife's dystopian twin. And there were few people of immediate west African descent involved in UKG, whereas in grime they form maybe the majority element, or at least a very significant minority (of course, there were far fewer west Africans in London in the late 90s than there are now).
PAUG and So Solid were MC-led garage that paved the way for grime, but the production is slick and centred around off-beat hi hats, and the MCing is smooth, it flows around the beats like honey. If I was to identify the most African elements of grime, it would be the jagged, sample-heavy production and the raucousness in the MCing , particularly the trick crews have of splitting the bar into a call-and-response, which maybe grime's single biggest vocal meme and had no precedent in any UK urban music before 2002-ish that I can see. It's got much more in common with African and Carribean music like hiplife, soca and Kuduru - and all of them in thier modern form involve people rapping across 4x4 beats running at around 125-140 bpm, hence maybe why people coming to Britain out of those subcultures felt an affinity with UKG.
In fairness to you and mos dan, the term 'grime' wasn't in currency with anyone I spoke to in Ghana. And Ghana as an anglophone country might be over-represented in grime compared to other west African nations because of the language connection.
And obviously the London-specific lyrics are, well, specific to London. But grime surely has to be about more than that, otherwise it's just urban Britpop (a concept that the more self consciously Lahhndan MCs skate dangerously close to IMO).
Grime is a hybrid music, but I stand by saying that it's roots are more west African than anything else. I'm not saying that Grime didn't develop in London, I'm just arguing for a recognition of it's international, African dimension. I'd like to see people looking at grime as African music influenced by UKG, rather than vice versa.