Apologies Liaquat - I was not aware that there was more than one supplier of those 1000 litre containers, with the metal frame around them. When I was researching this for my brother-in-law, the only supplier that I found in the greater Cape Town area was "Drum and Container" - I am not 100% sure about this, but I think that they actually manufacture those containers.
And according to them, these containers I am referring to (which look nearly exactly the same as yours) are indeed food safe, chemical safe, and safe for storing water for human consumption - as these containers are also used in rural areas for water storage units - according to the "Drum and Container".
BUT - I was incorrect in stating that that's where you got yours from. I made the big mistake of assumption.......
In any case Andreas - perhaps you can go through your local Yellow Pages, and see if any similar industrial company like "Drum and Container" exists in Durbs, and contact them yourself to see if they could perhaps supply the exact drums that you are looking for (I think for your specific use then, as you explained) that 60 or 70 litre drums would be far better, as they are still movable, and should not take up TOO much space.
I am QUITE sure that you should be able to get them cheaper at an Industrial / manufacturer than at Makro....