Let's try this again, first the pics...
You can try another way, but you have to go all in, like committing all your chips in a poker game.
Thin the plastic from the back side, and cut out the radio access panel. You could use a sharp blade point, but because of those curved corners, it might be better using a sharp pin or other sharp tool, and repeatedly score around the panel until you break through the plastic.
Once this is done, clean up both the opening and panel edges with some sanding. Then re-attach to the desired depth. There also appears to be a hinge running across the top. To simulate this take an appropriate length of stretched sprue and after it is attached, brush some liquid cement across it and make vertical notches.
regards
Jack
p.s. forgot to mention while looking for some pics, ran across a review of the kit and it did state the cockpit was too shallow. So that would explain why the rudder pedals look too long.