Just ask Zen if they�ve put any TRC banding on the install ... just as belt and braces.

Here is an image with all the sections separated: Master Socket 5C + MK4 Faceplate not too sure if you have a MK4 filtered face plate so where exactly is your extension cable (Ethernet cable) connected to the crewed down pushfit crimp terminal with 5 3 2 written on it, or is it connected to the clip off front plate to the terminals.

So going by my attached picture looking at the middle and bottom parts, are you saying its connected to the middle section or the bottom section.

Middle would make it a phone extension, bottom would make it a data extension.

As for adding the extra few meters may or may not make a difference, but you said you will be getting 1Mbits over ADSL, so you are already on a long line, I was trying to get the most out of your connection.

Sure adding length to the line adds attenuation due to losses in the cable, but filtering the phones + any other phone extesions reduses the chance in them inducing noise onto the line, which is why the ISP says try it in the test port on the master socket with all the removable faceplates removed.

BTW whats at the other end on the extension cable?
Like whats it terminated into?

There is noting stopping you from moving the extension from the phone extension terminals over to the data extension terminal assuming its a good Ethernet cable.
This is all assuming its currently a phone extension that is.

Paul