THANK YOU ALL FOR YOUR HELP.
I guess I didin't explain it fully enough, but IR Pirate and Jeffersen have it pretty right.
We actually fly in from Mauritius to Capetown. 6 days later I take the aircraft owners up to Johannesburg where they stay for 5 days. My family are going commercial from Oz to Capetown. When I go up to Joburg, they will stay in Capetown, so after landing in Joburg, I will lock the doors on the jet and then pax back down to Capetown to rejoin my family and head off down to the beautiful Garden Route to explore and relax.
Hope that answers some of the questions about my seemingly "dumb" trip planning.
ZS-FOY. You asked "why worry about costs when you can afford to fly a bizjet from Oz to ZA." I know on the face of it that is a fair question. But time in Corporate flying for extremely wealthy people teaches one that, despite fabulous wealth, high wealth individuals tend to watch the bottom line just as hard as you and I. My job as Captain is to get them where they need to be safely and efficiently and in generally the most cost effective way. If I can't do that then I will probably lose the best job on the planet.
Thank you all again very very much. Lanseria it is, and I will use Pirates advice and try to fly Lanseria back to CPT.
Trev