Do you have any advice for potential travellers?
You may only have 90 mins to catch your connecting flight at Jo'berg. That might sound like a lot but don't get complacent. I suggest when you are checking in online that you pick a seat as close to the exit as possible to give you more time. Follow the crowds to immigration. If you're a UK citizen, opt for the lane for non SA citizens where Visas are not needed. Getting through here could take a while, so be warned. Once you're through and have picked up your luggage, follow the signs for domestic flights and recheck in your luggage. You don't have far to go. When done, go to domestic departures. Ignore/avoid unofficial/non Uniformed people who try to help you, they will ask you for money for their assistance.
Bring your own tea & coffee, not all rooms will offer this. Hair Dryer too but at the Tsikigamma National Park you can always use the sea breeze.
If you want to avoid excessive UK data roaming rates, go to a phone store such as Vodacom and buy a local SIM Card. The card itself costs pennies. 1GB costs about R150 so is very cheap. So before you leave home, estimate how much you use per day and factor it up. If you're a regular on social media and upload a few photos a day, 1GB could easily last you around 5-6 days or even less! But don't forget to enjoy what's around you rather than what's happening on your phone! Wifi is available in places but is hit & miss and can be slow. South Africa's mountainous geography doesn't lend itself to wifi very well.