The only official abseiling in Lesotho takes place at Semonkong Lodge down the Maletsunyane Waterfall. This the highest commercial abseil in the world just over 200 metres.
nuts and bolts
The way to go about it is to book your accommodation at Semonkong Lodge and find out all about costs and details of the Abseil. You will do a smaller abseil the day before the main one, on a cliff close to the lodge which acts as your training session and the morning after its all systems go for the big one. Therefore you will need to allocate a day to get to Semonkong, and possibly arrange the practice session for the afternoon you arrive. Then you will need to allocate one full day for the Abseil as well as the celebratory evening in the Semonkong Pub.