Preparing before plastering

[loopylu]

we have had some sockets moved and the room is being replastered next week. what is best to fill in the wholes in the wall? Would the plasterer just fill in the channels? And for the square holes I'm guessing we need to put some board in? Or is there another way to do this

Thanks

 

[JohnD1963]

For the first pic. I would get a couple of lengths of 2x1 batten. Cut them an inch either side of the length of the hole and fix them in position with gyproc screws. Then cut out a bit of plasterboard the size of the hole and fix to the battens.
Second pic. Loosen the socket, isolate the circuit if you can. Buy a small bag of cement mix or bonding plaster. Use a small trowel or filler knife and apply it.