The anti venom you buy is a general anti venom that covers most snakes. You can only have them in the camp, as it must stay in the fridge. In RSA you are usually close to medical facilities. It will be better to get the patient as quickly as possible to hospital.

Snakes will only bite you if you provoke them, I had numerous encounters with snakes in bush but was never bitten. If you see a snake give him a chance to get away. Prevention is better than cure.