Just recently bought my first house, and organised Vodafone naked broadband (as it's fairly cheap when packaged with Sky. I researched providers for months before moving in - and saw Vodafone had achieved some great results in the Truenet tests.
The house I bought was previously owned by someone fairly high up in I.T. at Telecom - and he said the speed was decent here (I assumed he would have ensured it was amazing).
However, since setting it up I've faced constant disconnections and random slowdowns. At times when it disconnects, it won't automatically reconnect (even overnight) and I need to reset the modem to regain a connection.
For example just ran Vodafone's speed test:

The latency is insane. But it's not always like that - I've run speedtests at various times and the best I've seen is 9Mbps down and 1 up and approx 29ms.
My place is on the border of Mt Eden and Balmoral - and definitely in the 'red zone'.
There's nothing else plugged into a jack in the house aside from the modem.
I should note I'm not using the standard Vodafone modem - instead I've got a Netgear N600 to improve the range.
There is a chance I haven't configured the modem correctly.
Settings:
PPPoA
NAT enabled
VC multiplexing
VPI 0
VCI 100
DSL mode: auto
Transfer mode: ATM
I should also note I'm using a jackpoint in the study with the label "R-NGT TRIAL" which I assume was a trial telecom was doing at some point.
Any help with this would be much appreciated!