Basutoland (now Lesotho) is a small country entirely surrounded by South Africa. Postal services to Cape Colony (which was administering the country at the time) were established in 1870. By 1884, the administration of the country had moved to direct Crown Rule from the UK, but postal services were administered by Cape Colony until Union in 1910.
Prior to Union of South Africa, Basutoland largely used stamps of Cape Colony although those of Orange Free State, Natal and Transvaal were also used. After Union, stamps of South Africa were used until Basutoland issued its first stamps in December 1933. Stamps of South Africa remained in use for around a year afterwards.
Prior to Union, there were around 39 post offices or postal agencies in Basutoland. Here's a few pages of these fore-runners, arranged by post office. There's at least one error in the scans (I've just spotted it). No prizes for finding it, but I'll correct it later for my own collection.
Jon, with some of the Maseru cancels I am still not 100% certain about them so I have opted for the commonest version in use at that time. Proud isn't as detailed as Putzel is for SWA, and knowledge of dimensions of the different cancels and letters in them would be helpful. The "SCUTH AFRICA" variety isn't recorded by Proud, but I'm sure Putzel would have seen it. It's fun, though!