After a long time waiting for a fix I decided to flash the phone with a newer version of firmware, currently not available in SA via official channels it seems. I looked for help from Vodacom but they could not get it fixed:
Just a heads up to anyone with this phone on Vodacom in SA.
Rooting was optional but I followed this guide to root and flash a generic version of ICS (4.0) on my wife's phone:
also see: http://naw32fsystem.blogspot.com/201...an-to-ics.html
Like all flashing/rooting you do it at your own risk, you might void the warranty and end up with a silly looking expensive doorstop.
Been running with 0 reboots since the 13th July. Fast and stable so far.