i feel that being middle class in kenya determined by your lifestyle more that income or where you live. Thats why you find a 45 year old guy with his own company and property all around nai with a 3 car garage living in Buru and a 25 year old earning 30k and living in a 20k sq in kile. the social economic classification of A, B, C1, C2 D & E is flawed as it focuses on income, residential area and only takes into account the bread winners income and not household income.
A better way would be the Living Standard Measure, LSM as we call it that divides the Kenyan population in 17 LSM with 1 being the poorest & LSM 17 being the richest. Middle class from an LSM perspective starts from LSM 7 to around LSM 13 being based on the standard of living.