If you start with-lets say-a JAA CPL, then convert it into an african license....you can easily "upgrade" to an ATPL.....then convert it back into a (now) EASA ATPL.....but this will be considered as a "conversion"-so you canīt "convert" it again into another license.....therefor you will need a "standalone" ATPL..
Despite the information given on their website:
They ONLY hire TYPE RATED pilots....
(Got in contact with their chief pilot last week, as a friend of mine was looking for a job with them....).