I have since made a few other enquiries. Here is my understanding:
If the ETF/share you receive dividends from trades in a country that has a tax agreement with South Africa then you can claim a rebate with SARS.
Using USA as an example: if you receive dividend income (as an individual RSA resident ) from a USA etf (VTI) bought through EE (or any broker) dollar account, VTI will withhold 15% of the dividend paid and when EE receives the dividends income from VTI (less 15%), they have to, buy RSA law, withhold 20% dividend income. I.e. you are effectively taxed twice.
Sars allows you a tax rebate that in effect reduces your taxable income for your tax return. SARS has a bunch of rules/formulas around that which I haven't yet mastered - getting there. But believe me, SARS will make sure they get their share.....and then some.