I have rung Vodafone who tell me it is a network issue due to a Conklin cabinet. They said look on Chorus' website to see when it will be upgraded.
I looked at the coverage map and our house (3km from the centre of Martinborough village) seems to be situated on a tract of land that falls between the UFB rollout in the village and the RBI rollout outside the village!
Thus we appear to be excluded from either - as are many other properties in that land tract.
We do not live in the middle of nowhere by any means and there are at least 20 houses within 1500m of mine, so why do we not seem to count?