"Kenyan" and "British" are poorly defined categories. They are not mutually exclusive. M-Pesa is a large and complex thing (company, product, service, cultural or economic effect, why not all of those things!)

So the answer is null.

And since people get so hung up on bs about categories, they will argue about it from an emotional instead of a rational perspective. Those arguments will be endless as (see first paragraph) there is no correct or provable answer.

It is important to do this analysis and remind ourselves of these facts whenever a poorly defined question arises involving complex systems (like culture, society, economics or politics).