This whole digestive saga gives one indigestion.
There is no requirement to inform one particular CAA that you hold a flying licence or a medical issued by another authority. If you hold either an FAA licence or medical or an EASA equivalent you are not obliged to inform the South African CAA that you do so nor, as far as I know, are you obliged to volunteer the fact of an OML imposed by one authority to another authority. But what you must not do of course is to lie to an authority and I think that advice has been given to the OP by absolutely everyone who has responded and of course, that is the right advice.