In reply to a post by Adsl24:

The engineer will only route the cables round the house, so e.g. along the skirting board, over internal doorframes etc. I very much double they will drill internal walls, or spend any great length of time on the extension.

My extension cable goes through a wall and was fitted by BT. If you think about this logically can you think of any way it can get from one room (say the hall/staircase) into another room (bedroom/study) without going through a wall or a ceiling.

I suppose they could just leave it lying on the carpet.

I very much double they will drill internal walls, or spend any great length of time on the extension.

That's just not true. Very often drill through internal walls, or door frames.

BT/OR did a good job for me.

New Master Socket in hallway, Data Extension cable routed over a door frame, drilled through an internal wall and Modem screwed to the wall in my study.

Took about an hour (excluding Tea and Jaffa Cakes).