We had recently removed a wall-mounted AC unit which left behind 2 large cutouts in the wall, the holes are 309mm x 245mm and 75mm x 70mm. I've seen plenty of discussions around how to patch up smaller holes with a filler but I'm unsure on how to fix large cutouts. How would I about fixing these?
As the holes appear to be close together the best option is to cut one big rectangular hole, Do not go higher or lower than needed, on the sides though cut the plaster out to the next stud so you can secure the new piece.
Be extra careful cutting out the plaster near pipes and cables inside the wall.