Try accessing the guide  on a different set of channel, 

From memory Each “mux” has a discrete set of epg data,  so tvnz channels 1,2 etc and seperate from 3, ( 3 bravo etc), 

Thanks you're spot-on, OK on 1,2,10  nothing on 3, 4 8.

Getting MHEG5 data from the Media Works mux hasn't been working for me for the last few days.  I am in Auckland using the Remurea Infill frequencies.

The last good load looks like it was on the 6 Sept (I think as I had data up to the 13 Sept).  Multiple loads run throughout today only have data from 31 Aug to 7 Sept.

I have just changed to the TVNZ mux and I have 7 days of data again.

So if it is the same issue you could try tuning to one of the TVNZ channels and wait a few minutes to see if the guide data to updates.