Any question answered...

Can anyone point me in the direction of a cross section of how a chimney is constructed in a typical Victorian (~ 1910 so I guess not strictly Victorian) terrace?

I want to feed a wire from the loft to the living room and the chimney seems the perfect option for this except regardless of how much I try dropping strings down from the loft or shoving cable rods up I can't get anywhere.

Cheers for all the suggestions here. I made another hole at the other side of the cap, dropped a weight on a string down and it worked first time. Can't believe I spent so much time trying to do it at the other side.

Next question. I'm planning on running a mains extension (max draw maybe 300w) and an Ethernet cable up there. Anything special to consider?