Stuart, thanks for this advice, can you just clarify the point above though. Those three pairs of wires that are on the faceplate at the moment, if I take them off and put them into the new adapter faceplate it does the job of filtering all the extensions etc in the house?

Yes, that's exactly what it does.

Terminals 2, 3 and 5 are the only ones required for the phones to work though. Others are often connected for neatness.

Top man, thank you sooooooooo much for your help, you've just saved me

I'm guessing you were meant to drop a link into something like a ADSL faceplate splitter?

Oops forgot the link! Thanks for finishing it off for me..