Are you sure that your friend was actually dealing with a valid South African agency, rather than a fraudulent website. (There are plenty of them out there!).
For UK applicants, South African visa applications are handled by VFS Global. (They're entirely reputable and provide visa services for several countries). Payments are made to 'VF Services UK Limited' and NOT to the South African Home Office (or anyone posing as such). The relevant government department in South Africa isn't even called the 'Home Office'; it's the 'Department of Home Affairs'.
Further, holders of UK passports are
exempt from South African visa requirements for stays of up to 90 days.
Further still, even people who are required to apply for South African visas should pay nothing like £950.00. The typical cost of most visas is £35.00, plus a further £35.00 administration fee, making £70.00 in total. Even an application for a permanent residence permit only costs £125.00, plus the £35.00 admin fee, making £160.00 in total, so I simply can't see where a £950.00 charge comes from.
If your friend applied online and used any website other than this one
http://www.vfsglobal.com/southafrica/uk/
(which is the ONLY site approved by the South African government) she has been SCAMMED BY FRAUDSTERS.