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Kenyan citizens generally need a Direct Airside Transit Visa to transfer in the UK even without leaving the transit zone of the airport.
In some cases one may be exempted from the DATV requirement, or be allowed to transit landside without a visa, but but none of those cases apply to you.
Some of the exceptions are for people who travel to or from the major Anglosphere countries with valid visas -- but Schengen countries (or, for that matter, Jamaica) are not on that list.
Then there's an exemptions for holders of a valid common-format residence permit from an EEA country of Switzerland. Since your permit is not common format (and the regulations to take pains to say "common format" whenever they mention this expcetion), that won't help you either.
So you need to apply for an appropriate visa.
(The Schengen countries themselves accept a wider range of each other's residence permits that are not in the common format, but that has no effect in the UK).