How would you fix this floor then?!

[gdallas]

Looking for the best/easiest way to repair this floor. It's how the builders left it. Used to be a built in vanity unit concealing it. A basin waste pipe which I have now removed, entered here to connect in to the soil pipe. I just need to patch this up so I can eventually ply over then tile.

They have cut this floor at weird and different angles! Animals!

Quick and easy preferred (if possible )

Thanks

 

[foxhole]

Square off the hole a much as possible , screw baton under across centre of hole and cut in a patch as near as dam . Then you can ply over , looks like it’s out of the way so no one going to be jumping on that area.Minimum 12mm ply ideally 18mm or hardibacker .