Sideface:boland: ... The wiring was all installed by the house lord, who had Vodafone cable. ADSL was split up, because he used to have 7 phones in the house...
You definitely need a master filter.
What you describe sounds like a fairly complex installation.
The tools you need will add to the cost - I would advise you to use a professional installer.
I presume that you are renting - if so, don't forget to ask permission from your landlord.
The only thing I want to do is to disconnect the ADSL line from the 7-RJ45-splitter and put it into the Master Splitter. From there to a RJ45/RJ11 socket and then to the modem. Easily reversible, right? Master Splitter costs +- NZD 30. Some tools can be bought for I assume NZD20? Installer costs NZD 150-200, so that's a big difference.
I am not sure why it should be that complicated?