What should I ask Stephen Jennings?

I will be doing a Conversation with him:

Stephen Jennings is the Founder & CEO of Rendeavour, Africa’s largest urban developer, with over 12,000 hectares (30,000 acres) of satellite city developments near high-growth cities in Kenya, Ghana, Nigeria, Zambia and Democratic Republic of Congo.

Link here.  I also know Stephen from his time working on reforms in New Zealand, way back when in the early 1990s.  Here are various links about Stephen.  So what should I ask?