I've moved 200 metres up the road (Karori, Wellington) and from a house that was built in the early 90's to an apartment built in the early 00's. There was also a change in providor from Telecom to Vodafone.
Normally I would just suck it up and move on, however I am hesitant to believe that it could be a wiring issue as other people I know living in the Northland / Karori region also constantly comment on how poor the Vodafone broadband offering is in this region. The plan we are on is the Naked Broadband "Entertain" (500GB) package.
My first step in trying to understand where the problem was, was to replace the Huawei device that Vodafone provided with a Draytek Vigor 120 + TP-Link device running Gargoyle. This didn't fix the problem, performance in my view is still pretty shocking.
Below is a screenshot from the Vigor 120 connection overview page which when compared against this post here would indicate that everything is in line.

So the question is, is this "normal" or should we be on the phone to Vodafone and looking at getting some further assistance?