2. I get the best connection upstairs in my bedroom, on a grey wire. From my investigation, the first wire splitting off the black wire is a grey wire. Probably the upstairs one right? You need to put a tone on an unused pair in the grey cable to find out where it goes.
3. How can I make sure the cables I clipped doesn't pick up noise, can I put a bit of silicone on the ends? Seal with a gel crimp