I already have ADSL Nation face place. Order it three years ago when we moved into this new build 🙂 And it is working great as we have no difference (well - almost none) between test socket connection and faceplate.
To be honest, as I now know about ADSL2+ adding some more Line attenuation will make this line unusable to ADSL2+.
However looking at the link provided it pointed me towards BT Business Hub (and i think i might have one at work that we are not using). I will be trying it myself even if I have to buy it. Seeing some people having connection speeds more than triple of my, on longer lines with much higher Line attenuation make me want to try. I will also look at this double shielded cable that might help however when I was trying my router connecting directly to test socket with short cable and router next to the socket I don't think it's internal interference.
Once again, thanks for everyone’s input - really appreciate it.