Some good news?? Hmmm, I'm not so sure...

So after many dicussions with the Traffic Dept and SARS, it appears that I don't need to go through all that hassle after all... there are two routes you can take to bring your car into South Africa, here they are with the pros and cons:

1. Import your car and document it via SARS/Customs
When your car reaches SA, Customs will clear it and give you a form (SAD 500) which, along with the other documents allows you to legally bring your car into the country, and more importantly, use it on SA roads without registering it etc.
Pros: No more paperwork to do at the Traffic Dept! Also, the clearing agent will do most of the work for you.
Cons: The temporary import permit is valid for a period of 6 months, after which it must be renewed (your clearing agent should do this for you). But as long as it's renewed regularly, it can go in indefinitely (I think). Also you must lodge a deposit with SARS for up to 80% of the value of the car. You get this back once you leave SA or become a permanent resident.

2. Carnet de Passage (via the AA in South Africa)
The Carnet is basically a passport for your car, and allows you to bring it into South Africa and use it. Only the AA in South Africa can issue this, and it needs to be done before you leave the country (it may be possible to get this from the UK AA, but you'd need to check) as it needs to be available to the shipping agent. Again, you do not need to register or license the car to use it in SA.
Pros: Can be done in advance, and no visits to the traffic dept.
Cons: The Carnet is only valid for one year, and apart from some leeway if you are delayed in leaving (or becoming a permanent resident) it cannot be extended. You must lodge a deposit of 100% of the value of the car, although this can be done as a bank guarantee/indemnity, rather that paying over the cash.

You must remember that, which ever route you choose, you must carry the relevant paperwork with you at all times. If you are stopped at a roadblock, you will need to prove the car is in SA legally.

This is the story so far - I am skeptical because it suddenly seems so easy, so I am still checking around to see whether there are any nasty surprises lurking!!

Change of story number 386...

OK, so today I was told yet ANOTHER version of what steps I need to take next (I didn't bother to write the others, as I wasn't sure it was that simple, but this is from a supervisor at the Traffic Dept, after I kicked up a fuss!)
So, allegedly, the next steps are as follows:
 - Collect import docs from clearing agent (there should be 3 or 4 different ones - ensure you get a receipt for your import deposit!)
 - go to Traffic Dept and fill out the Temporary/Special Permit form
 - Hand this form, plus a copy of your UK V5 document (your logbook), a copy of your Traffic Register document (as per the last post) and the import docs (my clerk didn't even bother to look at these, but some will depending on how thorough they are), plus the fee of R48.

They will give you two-thirds of a piece of A4 paper, printed with a large, temporary, registration plate. You put this in the window of your car, and it's valid for three days. NOTE: you are not allowed to carry passengers with this permit - only the person who applied for the permit may drive the car (unless someone collected the permit for you after filling in the Proxy part of the application form).
Once you have this permit, you need to go to the local Vehicle Dept where they will weigh and check the car, and verify it's not stolen, etc. If you're lucky the Traffic Dept can tell you where your local office is.
After this you can go back to the Traffic Dffice and apply for a NEW Temp permit (this time for 21 days, and you are allowed to drive the car as normal WITH passengers!), during which time you must take the car for the roadworthy test, after which you can FINALLY get the car registered, and with a proper 1-year licence.
That is the story so far, but I will update as appropriate - apologies for the babble: I wanted to type it all before I forget it!
Good luck, and don't forget some water for the ridiculous Traffic Dept queue!

Registering yourself

This is step one. Until you are registered in SA as a driver you can't do anything else.
You will need:
 - Form ANR, available here: Form ANR, second on the list
 - Two black-and-white passport-sized photos (there are usually shops nearby that will do these for you, costs around R15 to R20)
 - A large dose of patience

Fill out the ANR form, and take this with a copy of your passport (the one you mentioned in the ANR form) and your photos, and go to your local Traffic Dept office. Bear in mind that not all offices will provide this service, so check the list here (sorry Western Cape only!) before you go.
Be prepared to stand in the queue for an hour or more; bring some water, and maybe someone to trade places in the queue so you can sit down for a while - most of these centres have no air-con and can get very hot.
Good luck with step one!