Your UK allowances will not apply in South Africa, but you can view roaming costs at https://ee.co.uk/help/mobile/roaming/roaming-costs
If you're on PAYG, ensure your phone is used in the UK before travelling. If you're pay-monthly, text ROAMING to 150 before leaving the UK. These will ensure roaming is activated and your phone has access to South African networks.
Failure to do so will result in your phone not connecting to foreign networks and thus not having coverage abroad.
