I would soon be fitting the seatbacks so needed to have them ready. Not much work was required and it was an easy background task.
First I glued the locker opening flanges in place, simply weighting them down on the bench, as here.
When cured I cleaned them up and cut out the locker openings. I used a Japanese keyhole saw which I purchased for making holes for inspection ports and portholes. Here it is in use.
Cleaning up the edges was quick and easy using a saw rasp and a Spiraband abrasive wheel in the drill, like this.
Finally, the edges were finished off in the vice.
That's it! All ready for a test fitting.