al wrote:
I'm a little stuck! I have a light in my kitchen which works fine. I want
to add another light at the other end. To achieve this, I have been able to
run cable from that other end back to the switch box for the original light.
I cannot draw live feed from the ring as it is not accessible without
destroying stuff!

If all you want to do is have a second light which comes on exactly when
the first one does, you don't want to run a cable to the switch at all
at all. The cable for the new light wants to run to the ceiling rose of
the old light. There, you connect the earth to the earthing terminal
where all the existing earths go; the black to the existing
black-wire(s) and blue-light-flex terminal; and the red to the existing
brown-light-flex and single maybe-red
maybe-black-which-should-have-a-bit-of-red-sleeving-but-won't terminal.

And do get a decent book - the Collin's D-I-Y manual's pretty sound - to
get your head round the basics of house electrics. If you start feeling
unsure, get an electrician in - it's really not a good idea to stuff
about when you're as unsure which way is up as you seem to be...

Stefek