The above date is a guess but it was reported to the Johannesburg Star who reported that there were other witnesses in rearby suburbs.

The object appeared to have a row of windows like a passenger aircraft but it was difficult to make out the exact profile. I was in the garden with a friend when the object appeared over the northern horizon travelling south in complete silence at incredible speed it crossed from the north horizon to the south in about 6 seconds a distance of over 50kM.
Without anything to judge the scale of the craft I couldn't say if it were in the Earth's atmosphere or in space.
Witness indicates that the date is approximate.  PD