"Dave Liquorice" wrote
Simon Avery wrote:

Up to you. The plaster won't hurt it, and it's not mains nor gas nor
water, so it won't hurt anyone if you drill into it.

True but thing of the agro trying to repair it...

Steel capping is cheap and easy to fit. Though to be honest for LV
stuff like this I'd be looking at a larger duct, say 3" square in a
hidden corner somewhere even if it extends cable runs considerably.
'Cause as sure as eggs is eggs something will need to be changed or
added in the next 10 years.

Great, thanks for the advice, however after gouging a sample out. the
plaster is only 10mm thick, so there'll be very little covering it
when I plaster over.

Is there any mileage in going through the first course and threading
the wires down the cavity ? I don't think theres much chance in going
down through the plaster, as theres no space for conduit, so i'd have
to plaster over the 'bare' wires.

I may just go wireless !!

Cheers

Paul.