In case you have not yet removed the grab rail, I had a good look at this on Cape Whisper, hull 98. I have a small hole drilled near the top of the forward side of the cupboard through which I have passed the cable for my solar panel allowing it to exit through the forward hatch. I was able to peep through this and establish that the rail is, indeed, bolted through. I attach a blurry photo showing the bolt and nut coming through.
I then had a look at how one could access this through the cupboard, where the first thing which is in the way is the little shelf. I took a video looking vertically up the side of the cupboard and established that the shelf is screwed in with two screws into each side of the shelf, making it impossible to remove without damaging it. However something interesting is visible in the video I took, which shows screws coming through from front of the cupboard and an overlap which would indicate that the cupboard is a separate unit, screwed in place. So my betting is that if you remove the wooden frame around the cupboard door and unscrew four screws the whole cupboard will drop down. Another photo attached, viewing up the side of the cupboard showing the two shelf screws and a screw coming through from the cupboard frame (and my solar panel cable exiting at the top of the photo).
Bolt from grab rail.jpeg
Vertically up side of cupboard.jpeg
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