I`m fitting a heavy corner wall unit onto a wall which lies at 100 degrees (i.e when one face is flat to one wall there is a 20mm gap at the other at the extreme) .
There are no service gaps at the back ( 18mm butted carcass all around ).
I`m attaching using #12 screws with large flat washers to avoid `pull-through`.
Would you use vertical battons of the right thickness against the bad wall ( one batton would be about 10mm thick the other about 20mm thick ).
Or would you use another method.