Not a recommendation but just to say it's not as hard as it looks. The hole is covered by the base of the flap so you can make a right mess and it won't be seen.
If it's uPVC it'll be filled with foam. Take your point about the tools though. I needed a jigsaw and a drill to do one in my old place. I was lucky as the panel was easily removed so I did it flat and then popped it back in.