:::Jerry:::: wrote:

What if you have sockets on said skirtings though?

Then you would expect to find wires either vertically above or below
the said outlet.

Umm, the permitted-cable-routes explicitly allow *horizontal* runs from
visible accessories too... so not only would the clued-up
householder/electrician would consider the possibility of cables being
behind the skirting in an older property, but they're even Permitted
Under Current Regs. Admittedly, horizontal runs are rarer in practice
than vertical ones, but they're common enough in kitchens where there's
sockets all round the worktops...