UPDATE:
Thanks for all your responses, it's very much appreciated!
So i called Spark today, and to my surprise (sarcasm) they have suggested that for VDSL a master filter is NOT needed!
They then suggested to have a seperate rural 4G plan for the family to use at an extra cost of $90 p/month (I kid you not), while i continue to use the VDSL for myself for gaming lol. I don't even know how to respond to people like this... :/
So my question to you guys is; Do any of you know who i can call in the Christchurch region to get a Master Filter installed?
I'm sick of dealing with Spark, i'm not even going to bother wasting any more of my time with them, especially since they actually suggested i don't even need one! So i feel if i call them again asking for them to get a tech to install one, they will simply decline to install one, and state once again, that it's not needed when clearly it is! It even says on Sparks own website that a Master Filter is recommended for VDSL! lol