@africancoloner. the kiambu area that i know of with plot size restrictions is opposite muthithi in the kugeria neighbourhood.
Am working on a similar project in Kambu next to Runda and the planners are ok with it.
@moorings, you might have to 1st check with the kiambu county planners if such can be allowed at the land. If they dont, you might have to ask if a change of user application can be given to change the rules/byelaws .
As Iron Sharpens Iron, So one Man Sharpens Another.