Hi,
In the US, I have used Travelex and Fairfx debit cards. Works really well. Don't know if they do the Rand.
Basically, you send them the cash and they charge up a debit card for you.
There are many companies offering this service, but some charge for all withdrawals, some for recharging, some for ATM withdrawals. All will have charges for the Foreign Exchange between, say, pounds and dollars.
The two mentioned were among the best I found. Travelex gave you a spare card free, handy if one gets stolen or lost.
The handy thing with the FairFX one was that it is a Visa Electron, so avoided Ryanair charges. But that's now changed ;-(