Working for a guy today who completely gutted his kitchen, then broke his foot. May put an advert in A&E :-)
One of the jobs was to plasterboard a wall, directly over the existing plasterboard/stud wall.
In the area that was once between the work surface & wall units there were three double sockets. Removed the left hand one to fed the cables through the new plasterboard and found 4 x 2.5mm T&E cables crammed into it.
One was the power in and ran diagonally down from the ceiling passing through three studs on the way.
Two cables ran sockets above & below. Last cable seemed to run horizontally to the right towards the other sockets. Along the line between the sockets I noticed badly filled spots at roughly 600mm centres.
Subsequent piggling about revealed that the cable ran under the PB, out & over the timber stud, back under the PB, over the next stud, back under.... you get the idea. Held down on each stud with a cable clip. Went for a total run of about 3m.
I gave him the number of my electrician friend and got on with the other jobs.
Maybe Part P has it's uses.