Time to retune your Freeview box, or is it?

So people in the UK are having to retune their TVs today. What time do we have to retune them? Who knows. From the Freeview website:

I've heard I need to retune my Freeview equipment on or after 30/09/2009 - is this true?

Yes - all viewers with a Freeview digital TV or box (including homes with Top Up TV and BT Vision) will need to retune their equipment on or after Wednesday 30 September 2009, to continue receiving their available digital channels. On the day, viewers should retune from lunchtime onwards.

Lunchtime, well that's about as non-specific as possible. Why for heaven sake can't they publish the time the upgrades will be completed by?

It's 12:28 at the moment, is that lunchtime enough or is it still too early? I don't really want to retune the computer and have to do it again in an hour.