This reduced MCT is a glitch on the ET website - the official MCT is 45 minutes for International to International. Once you ticket the flight, you will most likely get an email from the ET South Africa sales team in 24-48 hours advising you that the connection is illegal and offering you a rebooking or refund. I've had this happen to colleagues booking ex-Durban last year.

If the booking slips through and you misconnect though, ET is very good about providing hotel and rebooking you on the next available ET flight. If you want rebooking on another airline, come armed with your planned itinerary and if it makes sense they will happily rebook you once you find someone who knows how to do it. They will rebook onto Star Alliance partners with barely a second look and to most of their interline partners if you push the issue. However, the initial offer will always be the next ET flight (with full hotel and meals provided until then).