It is very hard to download the contours in a non-overlapping block because the download tool overestimates the file sizes by a factor of 10. I split them up into 4 parts and they totaled less than 1 GB, not the 7.2GB estimate.
It would be useful to have a North and South Island region clip polygon. A crop box can be drawn around the South, but not the North.
We are working hard to try and resolve this issue. Other layers from the property and ownership dataset are also affected. Hopefully on Tuesday we should have a partial fix.
I will look at the option of a North and South Island region crop polygon. In the short term I can't guarantee that this will get the limit below 3gb.