It may be worth contacting the South African Institute for Distance Education (SAIDE) as they have developed ODL quality standards (I think together with NADEOSA). These may frame theoretically what you might been considering in relation to UNISA. I think Jenny Louw is still the SAIDE librarian and can be very helpful.
Here's a link to the studies related to your topic in RG as a kick-start response to your question. I am not from your area so I have not done such region specific research. I extend best wishes for every success with your research.
It may be worth contacting the South African Institute for Distance Education (SAIDE) as they have developed ODL quality standards (I think together with NADEOSA). These may frame theoretically what you might been considering in relation to UNISA. I think Jenny Louw is still the SAIDE librarian and can be very helpful.