I'm enjoying this story a lot. Growing up I remember reading old National Geographic Magazines about Rhodesia, and how it was one of the most beautiful areas in the world. To have seen it at a time when it was new to Western eyes would have been overwhelming. The photo of the bridge in the sunlight through the mists of Victoria Falls is perfect for this story. Did you take it yourself?
Jacob's family makes me think of those E.M.Forster, D.H.Lawrence, & Sommerset Maugham classic period tales. I think you're doing a great job with your characters. The way you portray them seems very real and authentic to the period, when roles were strictly conformed to, and the sense of doing one's duty was paramount.
I have a feeling that Jacob is in for quite an adventure, and he might have some of his peconceived notions challenged in Africa. He's obviously a highly adaptive person, so I can't wait to see how deals with the 'Dark Continent".