Contrary to what you might think we're still not "dead in the water" as per the previous post :-) The power was out from 07h30 till somewhere around 22h00 - but by that stage no one was in the building so we never actually saw it come back on.
We actually had to leave the main building by around 14h00 as the UPS was not going to keep us running forever. The system was rather impressive as we've been quoted a running time 6 hours without electricity and it definitely lasted longer than that. Mind you the only thing that we really need to keep running was the PABX and a single PC (which we turned off in the end).
So phones were running fine and the next issue came when I had to deal with Telewest. Loads of fights in trying to get our UK numbers diverted through to the contingency office. Definitely need to look at other options that might be available.
But in the end we survived and we learnt quite a bit. A number of quirks to be ironed out, but at the end of the day we can at least say that we did not lose service to our clients. Which is the most important thing really.
So I'm going to be having to deal with Telkom in the next few days to see whats available from this side of the world.