Thanks Keef - I will be when the time allows. I have explored ever which way to get a new wire down, including poking a hole through the ceiling in the wrong place which I now have to patch
. One more remote possibility left to try but I do not hold out any hope. Teaches me to stand over a builder while he does the work 'to spec' instead of going off to work.
Thanks for the tip on 'ring'. The modular stuff has a master/extension module option. If you need a web link to the stuff PM me, but Maplin have a limited range you can look at.