I'm in Auckland, and didnt really have this problem until about a month or so ago.
The speed between 6pm - 12am is soooo slow that it's not funny... I literally go into a youtube video, i've been on it for the last like 5 minutes, and it's loaded 33seconds.
I did the speed test and it gave me .30mb/s ........ And somehow, usually sometime between 11pm - 1am, the speed goes back to normal and is abnormally fast.
and I'm on the river-managed plan (not the unlimited one)