The main problem with measuring mains current is that you don't know whether you are looking at a mobile phone charger (2W) or a kettle (3000W). It is difficult to make devices accurate to 10% of 2W while capable of measuring or even surviving 3000W.
A current transformer like the one from RS would be a good start. It is rated at 5A nominal, 60 A max, so I would start with 4 turns on the primary, so that it wouldn't exceed the maximum current when the load is at the 15A max for the plugs in South Africa. That will give you 4 times the input and output current, so the nominal primary current would be 1.25 A. At .125 A, so 30W, with 4 turns, the output is quoted as being 4% below the nominal, so I would guess that you could go down to 5W or so and stay within 10% accuracy.