Re: good grief
"[...] but then ran into trouble when the 99999 numbers were inexplicably used up in less than two years,"
In South Africa in the 1970s your car had to get a new registration number if you moved town or area. IIRC you also had to get the vehicle "MoT" tested - even if it was only a few weeks old. If you didn't move area - your car never needed an "MoT".
These laws created several mini-industries. The obvious one was lots of shops making car new number plates.
Less obvious was the "MoT" test spin-offs. Only the government's local testing centre - usually only one per area - could do the official test. There were no appointments. You had to join the queue from about 5am - and come back the next day if you didn't get a test. You could hire people to spend the day queuing in your car.
A garage could do your pre-test to rectify any problems - and then handle the queue for you too. It was not unknown - after a successful "MoT" - for all the new parts to be stripped off and the old ones replaced.