I see TV1 and TV2 only seem to have this problem at the moment. There have been similar issues in the past where the data source disappears for a while, then comes back to life a few days later. I'll email our guy to let him know, but I think he monitors these forums also. 

Thanks Spong. I am pretty sure that there were more channels that didn't go past Friday or Saturday when I checked a couple of days ago, but you are right that it is currently only affecting TV1 and TV2.

It looks like it was a problem at the TVNZ end.  I was seeing smaller file sizes for the TiVo EPG uploads for the last couple of days, but on checking today's data this evening they were back to the usual size.  When I then checked my TiVo, it had the problem with TV1 and TV2.  So I did "TiVo > Messages & Settings > Settings > Network > Connect to The TiVo Service now" to get it to download the latest EPG data, and waited until that finished.  Then the EPG was good again on TV1 and TV2.

So it looks like TVNZ found the problem and corrected it before my EPG collection happened at 08:10 this morning.

Thanks. That's great news. Thanks for all that you do.