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.
Welcome to the Bunnings Workshop community @thezaza101. We're really pleased to have you join us and look forward to reading about all your projects and plans for around the house and garden.
Great to see you have already received helpful advice from @Humdinger. It sounds like an excellent suggestion to cut out one hole.
You would then just have to follow the directions in the video below or contained in this popular discussion - An easy way to repair holes in plaster walls
Hope that helps. Please don't hesitate to post again if you need any further assistance.