I aplogise in advance for even suggesting this very long shot who might, remotely possibly, have a contact somewhere.
I think it's unlikely you'll find a six seater anywhere in southern Africa or indeed in the entire sub continent. Apart from any other consideration something like a Cherokee Six is quite useful for ferrying loads of guns, drugs and slaves around. Why should anyone want one for a legitimate reason. Have you ever tried to sit in the back row of a Cessna 210/206?
African Flying Safari