Natives and people of all races need security systems. South Africa has a reputation for high levels of crime, so there is definitely a market for your products. Institutions and fancy hotels such as Cape Town accommodation install high level security systems so you should consider pitching to them.
I think you need to look at the existing security system selling businesses in South Africa. You can have a brief about their growth by doing some home work. This will help you to have an idea about how they started and how they are doing at present. By doing this you can too explore your business possibilities here.