Yes, I want to stop that line and have the broadband on the other line

Yes I've got a photo. How do I send it on this forum. Can't see a way to do it.

You'll have to post it on another site, like photobucket and then provide a link on here.

http://i1290.photobucket.com/albums/b534/WOODROYD1/J...
Cheers, this is the picture of the junction box.

Yep, that's a 16a. At a guess the black cable coming in from the bottom of the picture is the one from the pole, the 2nd black cable going off to the left goes to the front door/main line, and the brown down lead goes to the office line ?

Correct

I've had a thought. Could I get a new line installed, and then drop the redundant ones and have the main numbr switched to the new line.?

Again, sounds like a costly solution.