Nelson, or anywhere else for that matter. if it is fine during most of the day, but then slow at other times it could be due to local PON saturation, remember GPON is a shared network.
if you call into the care team they should be able to diagnose and if suitable get the LFC to possibly swap your PON segment.
Remember, Chorus make Gpon utilisation metrics available publicly - but no-one apart from me ever cared enough to download them or look at them.
Without even knowing what the OLT or port is though, I can tell you that level of performance on gig will 100%, absolutely NOT, be related to GPON segment congestion. (Because I have looked at them all, and sorted by highest - and even the worst in the country (on Chorus) is still good.
Cheers - N